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Inventory and Assessment of Forested Natural Areas on Bull Mountain
. . CITY OF TIGARD Inventory and Assessment of Forested Natural Areas on Bull Mountain Prepared for: The City of Tigard 13125 SW Hall Blvd. Tigard, OR 97223 503/639-4171 Prepared by: Arboreal Enterprises Michael R. Reichenbach Kristina A. Reichenbach 4422 Norfolk Street West Linn, OR 97068 503/656-7835 September, 1995 EXECUTIVE SUMMARY • An assessment of selected forested properties on Bull Mountain was conducted in April of 1995 by Mike and Kris Reichenbach of Arboreal Enterprises. A combination of aerial photo interpretation and to assess 1) Natural quality; 2) Linkages; and ground Special features. used All areas inspected showed signs of disturbance, either from harvesting or development. Since the completion of the Forested Natural Areas Inventory and Assessment in February of 1994, the number of acres of forest on Bull Mountain within the original study area has decreased from 156 acres to 64 acres. This decrease has significantly altered the type of forest remaining on Bull Mountain. Sixty-two percent of what was lost was upland Douglas-fir. Within the new study area, only 26 acres of upland Douglas-fir forest are not currently scheduled for development. Page ii Arboreal Enterprises City of Tigard. Inventory and assessment of Forested Natural Areas on Bull Mountain September, 95 TABLE OF CONTENTS EXECUTIVE SUMMARY 11 CHAPTER 1. PURPOSE AND METHODS 1 CHAPTER 2. FINDINGS AND RECOMMENDATIONS 2 CHAPTER 3. RECOMMENDATIONS 4 APPENDIX 6 APPENDIX CONTENTS Appendix A. Definitions Appendix B. Ranking Methods Appendix C. Data Sheets for Each Unit Appendix D. Building with Trees Appendix E. Map Page Arboreal Enterprises City of Tigard. Inventory and Assessment of Forested Natural Areas on Bull Llountain September,95 CHAPTER 1. PURPOSE AND METHODS The City of Tigard commissioned Arboreal Enterprises to provide an assessment of remaining forested areas located on Bull Mountain, both within the City of Tigard and on unincorporated areas contiguous to the City. Y This is follow-up to a 1994 study conducted by Arboreal Enterprises that identified and evaluated forested natural areas within the Urban Growth Boundary of the City. The areas identified in this study differ from the are defined in the Forested Natural Areas Inventory °S sessment compled February of 1994 in several ways: 1)size, 2) configuration and 3) location. in The map in the Appendix, shows the areas assessed as a part of this study. Y The size and configuration of the forested areas differ from the 1994 stud since this study is a focus on forested ownerships rather than contiguousY forested areas. Finally, the geographic area inventoried and assessed focused on the Bull Mountain area and included unincorporated areas contiguous to the City. The 1994 study included all forested areas within the City of Tigard and excluded forested areas contiguous to the City. A combination of aerial photo interpretation and to assess 1) Natural quality; 2) Linkages; and ground Special features of was used forested properties on Bull Mountain. These three elements were evalu for all Forested Natural Areas. Details of the ranking ated presented in Appendix B. b methodology are Maps and aerial photographs were examined by Kris and Mike Reichen of Arboreal Enterprises, to identify Forested Natural Areas. IdentificationBach, forested areas and preliminary classification was based on black and white of aerial photographs at 1"=400'. Coverage was from 1994. An on-site inspection of properties was conducted by Mike Reichenbach, Arboreal Enterprises, and Duane Roberts, City of Tigard, in April of 1995. The ground survey was used to further define the characteristics of each forested area. For those areas where permission to enter the propertyco d not be obtained, an assessment was made based on information from hud aerial photographs and visual inspection from adjacent properties. Page 1 Arboreal Enterprises City of Tigard. Inventory and -Assessment of Forested Natural Areas on Bull Mountain September,95 CHAPTER 2. FINDINGS A total of 25 Forested properties or areas were inventoried and assesse These areas were mapped onto a 1" = 400' scale ma d' accompanies this report. P• A copy of the map All areas showed signs of disturbance, occurring either from harvesting development. A numeric ranking was determined for each area.' Rankingsor were higher for forest types that are uncommon or disappearing Bull Mountain study area. Table A lists each area and ts ranking. the A complete description of these areas can be found on the data sheets in the Appendix. Since the completion of the Forested Natural Areas Inventory and Assessment in February of 1994, the number of acres of forest on Bull Mountain and within the original study area has decreased by 59% acres to 64 acres). This decrease is the direct result of timber harvest and and 156 development. Douglas-fir forest is the forest type that is most ra i disappearing. This loss has significantly altered mix of forest t e�y remaining on Bull Mountain. YP s Sixty-two percent of what was lost was upland Douglas-fir forests. forest on the properties inventoried and assessed is predominatelyThe conifer and hardwood (50 acres), with 26 acres of conifer forest an15 ac of deciduous forest. The map in the appendix shows the location 15 each forested property or area. of each Within the new study area only 2 currently scheduled for developm 26 acresof on upland Dois uglas-fir forest are not to Douglas-fir forest, the forested character of Bull Mountain will preserve the be lost. The rankings used in this study should not be compared to those in the 1994 study of differences in ranking methods. The main difference between the ranking methods is this study because does not use size as a major criteria for determining rankinthat more detailed nature of this study. Also, in the 1934 study, three groupings based on obvious break points in the point spread. h g This is due to the Y forested areas wered grouped intos breaks were present. However, upland coniferous forest generally ranked 3.5 or hi complete description of the ranking method used is in c this study no obvious ix B. As of April. 199.5 and based on conversations with Duane Roberts. higher. .� Page 2 :Arboreal Enterprises City of Tigard.Inventory and Assessment of Forested Natural.Areas on Bull Mountain September,95 TABLE A. Forested Natural Areas Data Summary FORESTED Description NATURAL APPimate Site Ranking AREA Sizeizein Visit 49h Acres upland conifer INIEMMIN P-1 upland conifer n 6 est. MEM riparian deciduous and mix �© 59 upland mix MEM16 est. n upland conifer MEI MUM y MEN 491 riparian mixed n D-1 21 est. n IIIM upland conifer 11111/11111 y MEI MIMI upland mixMUM n IMAM upland conifer n Mil 1111131 S-1 riparian deciduous & upland mix n upland deciduous ,immumem©© P-2 upland mix n lltalli Mil 45b upland mix n 49k upland deciduous 111.111111 n 3 est. 49e r8 ©® riparian deciduous 49f riparian mixed 6.5 49b riparian deciduous6.9 B-i ©®upland mix 1.8 n KEEN upland conifer and riparian ©® 49j 4.7 nMEM 49c 1.8 © NR3 harvested 49d NR 49g 2.8 NR harvested 49a harvested NR 8.; Ini NR Higher rankings are an indication of higher natural quality, uncommon forest type or unusual vegetative feature. Coniferous U were rated higher than mixed or deciduous forests due to the loss rof this forests forest type within the study area. The rating system used is biased toward natural quality with coniferous forest most heavily favored. Although ratings include the value of linkages the rating as corridors and habitat for wildlife the does not evaluate the value of linkages for park or openspace. Areas with point differences of.5 points may be very similar in quality. Also, on those areas where no on-site inspection was made, the rankings are estimates. 3 NR = not ranked (because it has been harvested) Page 3 Arboreal Enterprises City of Tigard. inventory and Assessment of Forested Natural Areas on Bull Mountain September. 95 CHAPTER 3. RECOMMENDATIONS Efforts to protect natural areas should focus on those areas with higher rankings. Acquisition of higher ranked properties (3.5 and above) should be considered as a means for protecting these forested natural areas.4 However, a lower ranked property should not necessarily be excluded from consideration for acquisition since cost and linkages with existing or planned recreation or park areas may also influence such decisions. For example; on area S-1, purchase of this property may be strongly properties location in relation to existingCityg y influenced by this highly ranked property to the East and property held in a common operty to the a ea oto the South. On some properties protecting the values associated with the forested areas during development may be possible if 1. Those values are identified and incorporated into the development plans, 2. Effort is taken to protect the forested areas during development and, 3. Information about the protected areas is provided to new residents so that landscaping around the new development areas is compatible with the protected areas. Specifically, on areas 49b, 49e, 49f, and in other riparian deciduous or mixed forest, building might be limited to areas outside of the riparian corridor. This corridor should be wider than the floodplain. The width of the corrido will depend on the size of the stream, the vegetation r betatron stream and the type of develgrowing along the development. In a residential setting, house setback from street might be reduced to allow for larger then financial or other incentives might be provided to homeowners t that maintai the corridors in a natural condition. Alternatively, the City may wish to n purchase land along these streams to developbike and w to the paths found throughout the City. alkinb paths similar Wile the preservation of individual trees will not maintain the natural quality or character of Bull Mountain, actions should be taken to encourage landowners to retain trees within forested natural areas. Theseg might include a combination of 1) Regulations, such as requiring a re ew of the site and approval of site plans by a certified arborist or consulting 4 Areas rated above 3.5 were either upland conifer or mixed forest types Page 4 Arboreal Enterprises City of Tigard. Inventory and assessment of Forested Natural Areas on Bull Mountain September, 95 urban forester prior to development; 2) Incentives, such as allowing flexibility in structure setbacks, road widths and grade; 3) Educational efforts such as providing information to the landowners about how to ret and protect trees during development. a><n Trees selected for retention on developing For example, Douglas-fir frequently fails fters a stand is openeld be d. Treeefully. removal and replanting with native species may be the only to reduce risk from windthrow while ensuringcontinuity practical means vegetation of the area. The Appendix Y in the natural retention and development. contains a reference regarding tree Finery, on public sites, interpretive information about the site and the reasons for its preservation should be developed. Interpretive sites can set an example, help develop community understanding and encourage public involvement in the preservation of the community's natural heritage. Page 5 _Arboreal Enterprises City of Tigard. Inventory and Assessment of Forested Natural Areas on Bull Mountain September.95 • APPENDIX CONTENTS Appendix A. Definitions Appendix B. Ranking Methods Appendix C. Data Sheets for Each Unit Appendix D. Building Appendix E. Mwith Trees Map Page 6 Arboreal Enterprises City of Tigard. Inventory and.Assessment of Forested Natural Areas on Bull Mountain September. 95 Appendix A. Definitions Arboreal Enterprises City of Tigard Inventory and Assessment of Forested Natural.areas on Bull Mountain September.95 Appendix A. Definitions The following definitions are used in this report. Forest: An area of greater than 5 acres in size, having woody vegetation capable of growing to heights of over 15 feet, with a canopy cover of at least 30% of the surface area. Roadside, streamside and shelterbelt strips of trees must have a crown width of at least 120 feet to qualify as forestland. Unimproved roads, trails and streams, or other bodies of water or clearings in forested areas are classified as forestland if they are less than 120 feet wide. The area must be capable of being sustained in a forested Condition Grove: An area of trees of less than 5 acres, that otherwise meets the definition of a forest. Natural Area: "a landscape unit (a) composed of plant and animal communities, water bodies, soil, and rock, (b) largely devoid of man-made structures, and (c) maintained and managed in such a way as to promote or enhance populations of wildli.fe.s a Iverson, L.R.. R.L. Oliver. D.P. Tucker, P.G. Risser, C.D. Burnett, and R.G. Rayburn. 1989. Forest Resources of Illinois: an Atlas and analysis of Spatial and Temporal Trends. Illinois Natural History Survey Special Publication 11. 181p. 6 Poracsky. J.. L. Sharp. E. Lev, and M. Scott. 1992. Metropolitan Greenspaces Program Data analysis: Summary Conclusions and Recommendations. Final Report. Metro. 600 NE Grand Ave. Portland Oregon. Page 1. Arboreal Enterprises City of Tigard. Inventory and Assessment of Forested Natural Areas on Bull Mountain September,95 Appendix B. Ranking Methods • Arboreal Enterprises City of Tigard, Inventory and assessment of Forested Natural.-\yeas on Bull Mountain September. 95 Appendix B. Ranking Methods An assumption was made about the value of forested areas and about t desires of the general population with regardhe assumed that the general public values later tages of presesuccession moreg forested areas. I early successional stages. This can be supported than large old trees and old growth qualities in a dforest. I also ae ssumed thatlic's a for forests are more likely to be representative of presettlement vegetation. older Ecosystems representative of communities found duringnt generally be more stable and support the widest array of natural florat d fauna. On the basis of these assumptions, high quality Forested Natural Areas reflect a natural succession of plant communities and are undisturbed human activity, or if disturbed, can easily be restored to a naturalby The highest quality would be an area that reflects the natural condition state . the time of settlement, circa 1840. tron at The potential value of the forested natural areas was ranked using system. This system uses the sum of three criteria: 1) Natural quality;numeric Linkages; and 3) Unique features. Table A: Ranking ) Ranges shows these criteria with their range of values. This Value accounts for natural quality, wildlife value, aesthetic value, and recreational value. Higher ranked areas will be more likely than lower ranked be or to contain areas that are worthy of preservation efforts.be to TABLE A. Ranking Criteria and Value Ranges. ELEMENT RANKING low numbers indicate a lower quality,reduced linkage or no presence of unique features in Natural •utility comonrison to other areas Linkages to other Natural Areas 1, 2 3> 4, or 5 Presence of unique features, wetlands, 0, .5, or 1 recreation potential or rare threatened or 0, 1, 2, or 3 endangered species The costs of acquisition, cost of restoration, cost of future maintenan current and ownership, were purposely excluded from the rankingce, To make direct comparisons between properties, size was also excludedreces froo. m Arboreal Enterprises City of Tigard. Inventory and.assessment of Forested Natural Areas on gull Mountain September. 95 the ranking process. Each of the criteria and their individual rankings are explained in the following sections. g Natural Quality Natural quality is related to the amount of disturbance evident and the successional stage. The grading system is modified from a system used in Illinois by White.' The range of values is from 1 to 5 based on the following: points: Relatively stable or undisturbed forested area. For example, A forest rated at 5 points would exhibit characteristics of an old growth forest, the dominant species would be representative of presettlement forests, and few indicators of disturbance would be evident. A forest area dominated by native conifers aged over 150 years having dead snags and large woody debris would be evidence of a forested area that would be score 5 points. 4 points: Old second growth or late successional or lightly disturbed communities. 3 points: Maturing forest stands, mid successional or moderatel to heavily disturbed forested communities. For exampleY mature second growth forests. P . Young to 2 points: Young stands, early successional or severely disturbed communities. This includes forested areas where succession has stopped due to human activity. 1 point: Very young, very early successional or very severely disturbed communities. For example, this would include recentl clearcut forests that are beginning to regenerate. Y Linkages to Other Natural Areas Many of the Forested Natural Areas in Tigard are small and fragmented thus they will not support the original natural diversity of plant and animal populations. While corridors between highly fragmented natural areas do Y pport breeding populations of animals that need unfragmented habitat, corridors do allow animals to move between natural areas. White. John. 1978. Illinois Natural Areas Inventory Technical Report, Volume I Survey Methods and Results. Natural Land Institute and Department of Landscape architecture University of Illinois. Arboreal Enterprises City of Tigard. Inventory and Assessment of Forested Natural.areas on Bull Mountain September.95 Linkages may are also important in the development of trail systems linkin public parks and other open space. g The ratings for linkage are as follows: 1 High linkage to other natural areas or open spaces present .5 Medium linkage to other natural areas or open spaces possible through undeveloped private lands 0 None linkage to other natural areas not possible Special Features Special features, such as the presence of a rare or endangered species, and wetlands, received 1 point each, up to a total of 3 points. _Arboreal Enterprises City of Tigard. Inventory and_Assessment of Forested Natural_Areas on Bull Mountain September.95 Appendix C. Data Sheets Arboreal Enterpr;ses City of Tigard. Inventory and assessment of Forested Natural Areas on Bull Mountain September,95 • City of Tigard Forest Areas Inventory Data Sheet Page 1 1 ?NATURAL AREA 2 I Ownershi• 45a IIIDATE of evaluation Private 4 CATEGORY 412971995: viewed from Lauren Lane VEGETATION TYPE Forested 5 upland or riparian conifer, mix, deciduous or shrub 6 CANOPY CLOSURE upland deciduous closed,open, scattered riCOMMON TREE closed SPECIES Estimated number of I red alder or bigleaf maple 8 trees per acre Estimated average size of I uk 9 major tree species 10 Estimated age of major I uk tree species IFOREST TYPE, abundant, uk common, uncommon SUCCESSION common 12 very early, early mature, late or ! old growth 131 Approx. Number of Acres early successional 14 PRESENT USE 2 (SITE VALUES forest 151 wildlife, trail, corridor protection etc. OTHER COMMENTS 16 , 1 ;RANK NATURAL QUALITY 1 to 5 !RANK LINKAGES 3 3 (0 to 1 (none. low &high) I RANK FEATURES, 0 to 3 1 0 5 ;TOTAL RANK 0 3 (est., no on site visit) Prepared by Mike Reichenbach Appendix C TIGDAT.2. ,s 1995 • City of Tigard Forest Areas Inventory 2 Data Sheet Page • 1 I NATURAL AREA i 2 Ownershi• 46 eb 3 'DATE of evaluation I Private II 4 CATEGORY 4/29/1995: viewed from Lauren Lane VEGETATION TYPE Forested 5 upland or riparian conifer, mix, deciduous or shrub 6 'CANOPY CLOSURE upland mix closed,open, scattered COMMON TREE closed SPECIES 3 Estimated number of Douglas-fir, bigleaf maple trees per acre Estimated average size of uk 9 major tree species 10 Estimated age of major j uk tree species i FOREST TYPE, abundant. uk 11 common, uncommon I I SUCCESSION I common 12 very early, early mature, late or old growth 13IApprox. Number of Acres mature 14!PRESENT USE 7 ,SITE VALUES forest 151 wildlife, trail, corridor 1 protection etc. OTHER COMMENTS i 16j I 1 'RANK NATURAL ;QUALITY 1 to 5 ;RANK LINKAGES 3 3 0 to 1 (none, low & high) I RANK FEATURES. 0 to 3 1 0 4 5 'TOTAL RANK 0 3 (est., no on-site visit) Prepared by Mike Reichenbach Appendix C TIGDATA2.XI,s 1995 City of Tigard Forest Areas Inventory Data Sheet Page 3 1 I NATURAL AREA i 2 I Ownershi. i 49ea 3 DATE of evaluation i Private 4 I CATEGORY 4/22/95 VEGETATION TYPE Harvested upland or riparian 5 conifer, mix, deciduous or shrub 6 CANOPY CLOSURE upland conifer closed, open, scattered scattered, su ICOMMON TREE suppressed trees that may blow down or die SPECIES 8 Estimated number of Douglas fix trees per acre Estimated average size of less than 200 free to grow 9 major tree species 10Estimated age of major 12-14 inches dbh tree species 'FOREST TYPE, abundant, 60- 70 years, based on ring count 11 common, uncommon SUCCESSION n/a l very early. early 12 partial cut in 1994-95, replanting is recommended(and may be mature, late or required by state regulations unless the land is being converted old growth 1 Approx. Number of Acres to other uses) 13 14 I PRESENT USE 8.7 acres 'SITE VALUES 151 wildlife, trail, corridor 1 This area is used by a variety of bird species and if left protection etc. , (OTHER COMMENTSi undeveloped will provide browse for deer 16 residual stand is subject to windthrow, the majority of these trees should not be retained if the site is developed for homes 1 RANK NATURAL QUALITY 1 to 5 I R ANK LINEAGES 3 10 to 1 (none, low & high) RANK FEATURES, 0 to 3 4 . 5 i TOTAL RANK i Not Ranked, (harvested) Prepared by Mike Reichenbach Appendix C TIGDATA.2.yLS 1995 City of Tigard Forest Areas Inventory Data Sheet Page 4 1 ;NATURAL AREA 2 Ownershi• 496 3 DATE of evaluation 4 CATEGORY 4122195 VEGETATION TYPE Forested 5 upland or riparian conifer, mix, deciduous or shrub CANOPY CLOSURE 6 ! riparian deciduous closed,open, scattered COMMON TREE closed ` SPECIES red alder. big-leaf maple, some Western red cedar 8 'Estimated number of trees per acre Estimated average size of 9 major tree species 12 - 18 inches dbh (with occasional larger) Estimated age of major 10' tree species 60 to 100 years, based on ring counts 'FOREST TYPE. abundant, 11 common, uncommon !SUCCESSION common 19 I very early, early mature• late or old growth Approx. Number of Acres maturing maple stand 13 6.9 acres 14!PRESENT USE selective harvest of individual trees (usually Douglas-fir)within !SITE VALUES this area 15iwildlife, trail• corridor protection etc. !OTHER COIMIENTS wildlife. trail, corridor roughly equal numbers of alder and bigleaf male, clear 16: recent selective harvest of Douglas fir, ravine 20 feet depp with running water; This area has high linkage potential with existing City owned property to the Southeast 1 RANK NATURAL 'QUALITY 1 to 5 (intrusion for harvest of conifer reduced quality) 2 RANK LINKAGES 3 0 to 1 (none, low &high) I I R-1N K FEATURES. 0 to 3 I 0.5 4 5 'TOTAL RANK 0 2.5 Prepared by Mike Reichenbach TIGDaT. 5 Appendix C 1995 • City of Tigard Forest Areas Inventory Data Sheet Page 5 1 INATURAL AREA I ®Owners hi. 49c 3 'DATE of evaluation I Private I 4 CATEGORY I 4/22/95 VEGETATION TYPE harvested 5 upland or riparian conifer, mix, deciduous or shrub 6 /CANOPY CLOSURE i mix closed, open, scattered COMMON TREE I open SPECIES I 8 'Estimated number of Douglas fir and big-leaf maple trees per acre ; Estimated average size of I Less than 200 9 major tree species lO;Estimated age of major 12 inches dbh 'tree species i FOREST TYPE. abundant, 60- 100 years 11 common, uncommon (SUCCESSION n/a 12 very early, early mature, late or old growth Approx. Number of Acres I early 13I 14/PRESENT USE 2.3 acres i 'SITE VALUESharvested 15iwildlife, trail, corridor protection etc. 'OTHER COMMENTS wildlife I 16; The remaining trees may blow down and, in general, should not be retained if the site is developed I 11 RANK NATURAL 'Q UA.LITY 1 to 5 RANK LINEAGES 3 0 to 1 (none, low & high) !RANK FEATURES. 0 to 3 4 i 5 !TOTAL RANK Not Ranked. (harvested) Prepared by Mike Reichenbach Appendix C TIGDATA2_VI,S 1995 City of Tigard Forest Areas Inventory Data Sheet Page 6 1 I NATURAL AREA 2 ;Ownership I 49d 3 1 DATE of evaluation Private 4 j CATEGORY 4/22/95 VEGETATION TYPE harvested 5 upland or riparian conifer, mix, deciduous or shrub 6 CANOPY CLOSURE I upland mix closed, open, scattered COMIVION TREE open (SPECIES 8 !Estimated number of big-leafed maple 1 trees per acre Estimated average size of less than 200 9 major tree species 10'Estimated age of major tree species !FOREST TYPE, abundant, 60 - 100 years 11 (common, uncommon 1 SUCCESSION n/a 12 very early, early mature, late or old growth !Approx. Number of Acres early 131 14'PRESENT USE ( 2.8 acres SITE VALUES harvested 151 wildlife, trail, corridor protection etc. I OTHER CONLMENTS wildlife 16 harvested I RANK NATURAL, U.ALI Q TY" 1 to 5 FLANK LINKAGES 3 i0 to 1 (none, low & high) /RANK FEATURES. 0 to 3 4 1 5 !TOTAL, RANK Not Ranked. (harvested) Prepared by Mike Reichenbach Appendix C TIGDAT�.2.\LS 1995 City of Tigard Forest Areas Inventory Data Sheet Page 7 1 NATURAL AREA 2 !Ownership 49e 3 DATE of evaluation Private I ©CATEGORY 4/22/95 VEGETATION TYPE Forested 5 upland or riparian conifer, mix. deciduous or shrub 6 + riparian deciduous • CANOPY CLOSURE closed, open, scattered COMMON TREE closed ,. (SPECIES 8 (Estimated number of red alder. big-leaf maple trees per acre Estimated average size of 9 major tree species 10 j Estimated age of major 16 24 inches dbh !tree species 1 FOREST TYPE, abundant, j greater than 60 11 common, uncommon SUCCESSION I common 1,I very early, early I mature, late or old growth 13'Approx. Number of Acres mature 14!PRESENT USE 2.3 acres SITE :�I,�S selective harvesting of conifer 151 wildlife, trail, corridor protection etc. ►OTHER COMMENTSwildlife and trails I 16 selective harvest of conifer has occurred adjacent to the I waterway 1 RANK NATURAL 'QUALITY 1 to 5 RANK LINKAGES 2 3 JO to 1 (none, low & high) i RANK FEATURES, 0 to 3 0.5 4 1 5 'TOTAL RANK ; 0 2.5 Prepared by Mike Reichenbach Appendix C TIGDATA2. ,S 1995 City of Tigard Forest Areas Inventory Data Sheet Page 8 1 NATURAL AREA 2 Ownershi. 49 3 DATE of evaluation Private 4 I CATEGORY 4122/95 IVEGETATION TYPE Forested upland or riparian conifer, mix, deciduous or shrub ifCANOPY CLOSURE riparian mixed closed, open, scattered closed ith openings from harvest of +COMMON TREE red alder & big-leaf maple with Western red cedar towards o conifer (SPECIES 8 Estimated number of j end trees per acre Estimated average size of 9 major tree species big-leaf maple= 14-20 inches dbh, cedar = 14 inches and less in CI Estimated age of major I dbh tree species FOREST TYPE,abundant, ' 60 or more years 11 common, uncommon SUCCESSION it common 1 very early, early mature, late or old growth early-mature maple with some up to 3 feet dbh !Approx. Number of Acres 13111 14!PRESENT USE 6.5 acres 1 'SITE VALUES 151 wildlife, trail, corridor protection etc. ►OTHER COMMENTS wildlife - hazelnut understory I 161 I I i D.fir removed from riparian areas 1 IRNK NATURAL QUALITY 1 to 5 j 2 :RANK LINEAGES 3 I0 to 1 (none, low &high) RANK FEATURES. 0 to 3 0.5 1 4 i 5 TOTAL RANK 0 9.5 Prepared by Mike Reichenbach AppendixC TIGDATA2.VLS 1995 City of Tigard Forest Areas Inventory Data Sheet Page 9 1 !NATURAL AREA 2 Ownership 49e 3 DATE of evaluation Private 1 4 CATEGORY 4/22/95 IVEGETATION TYPE harvested upland or riparian conifer, mix, deciduous or shrub 6 CANOPY CLOSURE harvested closed, open, scattered ! COMMON TREE i open SPECIES 8 !Estimated number of Douglas fir trees per acre /Estimated average size of 9 major tree species ! 10 Estimated age of major tree species 1 FOREST TYPE, abundant, 60- 100 years 11 common, uncommon IJSUCCESSION n/a very early, early 121 mature, late or 1 old growth Approx. Number of Acres i early 131 ! i4'PRESENT USE i 3 acres SITE VALUES 151 wildlife, trail, corridor protection etc. +OTHER COMMENTS wildlife 16; i ! 14"diameter limit cut. root rot noted in harvested area ;RANK NATURAL 1 !QUALITY 1 to 5 1 R ANIS LINKAGES 3 10 to 1 (none, low &high) ;RANK FEATURES, 0 to 3 4 I 5 ;TOTAL RANK Not Ranked. (harvested) Prepared by Mike Reichenbach Appendix C TIGDATA.2.V,S 1995 City of Tigard Forest Areas Inventory Data Sheet Page 10 1 NATURAL AREA 2 I Ownershi. 49h 3 IDATE of evaluation Private 4 CATEGORY 4/22/1995 viewed from adjacent property VEGETATION TYPE Forested 5 upland or riparian conifer, mix, deciduous or shrub 6 (CANOPY CLOSURE upland conifer closed, open, scattered COIV111ION TREE closed SPECIES 8 !Estimated number of Douglas fir trees per acre Estimated average size of unknown 9 major tree species I 18-28" and greater 10/Estimated age of major tree species FOREST TYPE, abundant. 60 - 100 years 11 common, uncommon uncommon in study area SUCCESSION 1�i very early early ! mature, late or . I old growth i Approx. Number of Acres I mature 13� 14 I PRESENT USE 3.4 acres SITE VALUES forest 151 wildlife, trail, corridor protection etc. !OTHER COMMENTS ! wildlife 16; 1 j R ANIi NATURAL !QUALITY 1 to 5 RANK LINK G ES 4 3 10 to 1 (none, low & high) i jR_��TIi FEATURES, 0 to 3 The! amount of Douglas-fir upland in the Bull Mountain0 � area has 4 I decreased to the point where it is uncommon. This stand also j has larger trees than other stands observed in the bull mountain 5 i TOTAL R:kvIi area, 2 6(est., no on-site visit) Prepared by Mike Reichenbnch Appendix C TIGDATA2.XIS 1995 City of Tigard Forest Areas Inventory Data Sheet Page 11 1 I NATURAL AREA I 2 IOwnership 1 49i 3 IDATE of evaluation Multiple ownerships I 4/22 & X1/29 viewed from adjacent property 4 CATEGORYI VEGETATION TYPE Forested upland or riparian conifer, mix. deciduous or shrub 113 CANOPY CLOSURE riparian mixed closed, open, scattered COMMON TREE open 7 SPECIES I 8 !Estimated number of Douglas fir, red alder, big-leaf maple ! trees per acre I Estimated average size of 9 I major tree species 10+Estimated age of major I I tree species FOREST TYPE, abundant. 11 common, uncommon !SUCCESSION common 12 j very early, early I mature, late or old growth young deciduous under mature conifer IApprox. Number of Acres 13I 14 IPRESENT USE 1 21 acres i jSITE V.AL[jES 151 wildlife, trail, corridor Iprotection etc. OTHER COMMENTS 16 I IDevelopment plans are in process for much of this area. There is potential for dedicated openspace as shown on the map. 1 I AI:NNATURAL 'Qu.-ALITI- 1 to 5 RANKLINKAGES 3 3 10 to 1 (none, low & high) I (RANK FEATURES. 0 to 3 i 1 4Ii 5 I TOTAL RANK0 4(est., no on-site visit) Prepared by Mike Reicbenbach Appendix C TIGDAT:U. ,S 1995 City of Tigard Forest Areas Inventory 2 Data Sheet Page L 1 !NATURAL AREA 2 Ownershi. 49j 3 1DATE of evaluation 4 CATEGORY 4/22/95 VEGETATION TYPE harvested upland or riparian 5 conifer, mix, deciduous or shrub CANOPY CLOSURE 6 upland mixed closed,open, scattered COMMON TREE open SPECIES Douglas fir. big-leaf maple, Western red cedar 8 /Estimated number of trees per acre Estimated average size of 9 major tree species 10 Estimated age of major less than 14 inches dbh tree species FOREST TYPE, abundant, 11'common. uncommon (SUCCESSION n/a 12! very early, early I mature, late or old growth Approx. Number of Acres 13 141PRESENT USE SITE VALUES 15 wildlife, trail, corridor , protection etc. OTHER CONRIENTS 1 16 !RANK NATURAL 1 'QU.ALITY1to5 RANK LINKAGES 3 10 to 1 (none, low & high) � RANK FEATURES, 0 to 3 4 ; 5 'TOTAL R,-kNK Not Ranked(harvested) LS Prepared by Mike Reichenbach Appendix C T1GDaTA.?.X95 1995 City of Tigard Forest Areas Inventory Data Sheet Page 13 1 (NATURAL AREA j 2 !Owners/1i. I 49k 3 DATE of evaluation i Private I 4 CATEGORY 4/22/95 VEGETATION TYPE Forested 5 upland or riparian conifer, mix, deciduous or shrub 6 !CANOPY CLOSURE upland deciduous closed, open, scattered COMMON TREE closed SPECIES Estimated number of ! big-leaf maple 8 I trees per acre Estimated average size of 9 major tree species 10 I Estimated age of major 12 16 inches dbh ;tree species 11IFOREST TYPE, abundant. common, uncommon !SUCCESSION common very early, early I`1 mature, late or I old growth !Approx. Number of Acres 13I 14 !PRESENT USE ;SITE VALUES forest 15! wildlife, trail, corridor protection etc. ,'OTHER COMMENTS wildlife 16! i I i mahonia and sword fern understory RANK NATURAL 1 'QUALITY I to 5 RANK LINKAGES 3 10 to 1 (none. low & high) FEATURES. 0 to 3 0.5 !RANK i 4 ' 5 'TOTAL RA0 2.5 Prepared by Mike Reichenbach Appendix C TIGDAT.-1?_.\ S 1995 • City of Tigard Forest Areas Inventory Data Sheet Page 14 1 NATURAL ARE 2 'Ownershi. 59 3 IDATE of evaluation ®CATEGORY 4/29/95 viewed from adjacent property VEGETATION TYPE Forested 5 upland or riparian conifer, mix, deciduous or shrub 6 CANOPY CLOSURE upland conifer closed, open, scattered COMMON TREE closed 7 ,SPECIES 8 Estimated number of trees per acre 'Estimated average size of 9 major tree species 10/Estimated age of major tree species FOREST TYPE, abundant. 70 - 90 years 11 common, uncommon SUCCESSION common 1,I very early, early I I mature, late or old growth I Approx. Number of Acres mature 13I 14'PRESENT USE I 16 acres !SITE VALUES 151 wildlife, trail, corridor i 11 protection etc. OTHER COMMENTS 16 1 RANK NATURAL QUALITY 1 to 5 RANK LINKAGES 3 j0 to 1 (none, low & high) RANK FEATURES, 0 to 3 ! 1 4 5 :TOTAL RANK 0 5 (est., no on-site visit) Prepared by Mike Reichenbach Appendix C TIGDaT.2.V 1995 ' City of Tigard Forest Areas Inventory Data Sheet Page 15 1 INATURAL AREA 1 2 'Ownershi, _1 3 DATE of evaluation i Private ©CATEGORY 4/29/9;evaluated from road IVEGETATION TYPE forested upland or riparian conifer, mix, deciduous or shrub 6 CANOPY CLOSURE upland conifer closed, open. scattered COMMON TREE closed ` !SPECIES 8 /Estimated number of I Douglas fir i trees per acre Estimated average size of 140-200 trees per acre 9 major tree species 10/Estimated age of major 8-24" ;tree species 'FOREST TYPE, abundant. I 60-80 years 11 'common. uncommonI I SUCCESSION uncommon in study area 1 very early, early mature. late or 1 I old growth 'Approx. Number of Acres early, mature 131 14/PRESENT USE SITE VALUES i forest 151 wildlife, trail, corridor protection etc. ;OTHER COM;LENTS wildlife, forest 16 1 Little disturbance, second growth forest 1 j RANI;NATURAL, !QUALITY 1 to RANI;LINKAGES 3 3 10 to 1 (none, low & high) RANI;FEATURES, 0 to 3 i 0_5 4 : 5 1TOTAL RANK0 3.5 (est., no on-site visit) Prepared by Mike Reichenbacb Appendix C TIGDAT. Vr 1995 City of Tigard Forest Areas Inventory Data Sheet Page 16 I (NATURAL AREA 1 2 !Ownershi. B-1 3 1DATE of evaluation 1 Private ©CATEGORY 4/29/95 viewed from road VEGETATION TYPE forested upland or riparian conifer, mix, deciduous or shrub el CANOPY CLOSURE I upland closed, open, scatteredcld j COMMON TREE Douglas-fir, western redcedar in understory, bigleaf maples on SPECIES 8 Estimated number of western end trees per acre I Estimated average size of W; 9 (major tree species 1 10 Estimated age of major j 8" to 3.5' tree species tik 'FOREST TYPE. abundant. j 11 common, uncommon ! I SUCCESSION j uncommon in study area 1 I very early, early ! mature, late or I 1 old growth j 13'Approx. Number of Acres I early, mature 14 PRESENT USE SITE VALUES i forest 15 wildlife, trail- corridor protection etc. (OTHER COMMENTSwildlife, forest t 16 several non-native plants were observed in the understorv: English ivy, English holly, and Washington hawthorne 1 !RANK NATURAL QUALITY 1 to 5 I RANK LINKAGES 2 3 ;0 to I (none, low & high) j RANK FEATURES- 0 to 3 0.5 4i 5 'TOTAL RANK0 2.5 (est., no on-site visit) Prepared by Mike Reichenbach Appendix C TIGD:ITA.2.X,5 1995 City'of Tigard Forest Areas Inventory Data Sheet Page 1 i 1 !NATURAL AREA f 2 !Ownership I City Property 3 I DATE of evaluation Public 4 CATEGORY 4!22/95 VEGETATION TYPE Forested upland or riparian 5 conifer, mix, deciduous or shrub 6 (CANOPY CLOSURE riparian deciduous closed,open, scattered COMMON TREE j closed SPECIES big-leaf maple, red alder 8 !Estimated number of with scattered Douglas-fir trees per acre Estimated average size of ! 9 major tree species maple=6 - 18 inches dbh, alder=6- 16 inches dbh 10 Estimated age of major I tree species FOREST TYPE, abundant, 11 common, uncommon common: 1,I!SUCCESSION uncommon form and quality of trees very early, early mature, late or i old growth 3 !Approx. Number of Acres mature 14 I PRESENT USE i Wildlife and utility corridor between developments SITE VALUES 15 wildlife, trail, corridor etc protection . ,OTHER COMMENTS NTS Wildlife and trail understory of elderberry, swordfern, and thimble berry, 161f uncommon tree quality clear trunks to 40 or more feet. good linkage with commonareas of adjacent development and City property. RANI;NATURAL 1 QUALITY 1 to 5 RANK LINKAGES 3 3 10 to 1 (none, low &high) ! j 1RANI;FEATURES, 0 to 3 1 4 ' I 5 !TOTAL RANK uncommon quality, 1 5 Prepared by Mike Reichenbach TIGDaT,�?1995 Appendix C 1995 City of Tigard Forest Areas Inventory Data Sheet Page 18 1 NATURAL AREA i 2 I Ownershi, i D-1 3 I DATE of evaluation Private 4 CATEGORY 4/29/95 VEGETATION TYPE f Forested 5 1 upland or riparian conifer, mix. deciduous or shrub CANOPY CLOSURE 6 I Upland Conifer closed, open, scattered COMMON TREE I Nearly Closed SPECIES 8 Estimated number of Douglas-fir trees per acre Estimated average size of 110 9 major tree species 10!Estimated age of major 1 19" tree species j FOREST TYPE, abundant, I 60 to 90 years 11'common, uncommon 'SUCCESSION uncommon in study area 1, , very early, early 1 mature. late or old growth Approx. Number of Acres I mature 131 i4'PRESENT USE i SITE VALUESmanaged forestland 151 wildlife, trail, corridor protection etc. ;OTHER COMMwildlife.wildlife, forestland i s site has been well managed. Because the weak and 16: suppressed trees have been removed from the stand the remaining trees are likely to withstand development. Good example of how to manage Douglas-fir in a forest or urban situation 1 1RANK NATURAL I The site is managed and therefore not ranked as highly on this !QU-kLITY 1 to 5 R_-1i�1Ii LINKAGES criteria. 2 3 i0 to 1 (none, low & high) RANK FEATURES. 0to3 0.5 i 4 ' i The quality of the area for a variety of uses has been improved 5 ;TOTAL R.�'�IIi through management, 1 3.5 Prepared by Mike Reichenbach Appendix C TIGD.aT5 1995 City of Tigard Forest Areas Inventory Data Sheet Page 19 1 !NATURAL AREA 2 i Ownership f G-1 3 'DATE of evaluation Private ( 4 'CATEGORY 4129/95 VEGETATION TYPE Forested upland or riparian 5 conifer, mix, deciduous or shrub 6 CANOPY CLOSURE upland mix closed,open, scattered COMMON TREE closed ` SPECIES 8 !Estimated number of birch, hazelnut, Douglas-fir trees per acre Estimated average size of j greater than 200 9 major tree species 10 Estimated age of major 6" 'tree species ;FOREST TYPE, abundant, 25-35 years for the birch 11 common, uncommon (SUCCESSION uncommon in study area 19 very early, early 1 mature, late or I old growth Approx. Number of Acres + very early 13 14 PRESENT USE SITE VALUES forest 151 wildlife, trail, corridor { protection etc. j OTHER COMMENTS wildlife This area was at one time a walnut orchard. One walnut tree 16; was found. The birch seeded in from surrounding landscape 1 plantings. This site is a good example of succession from a walnut orchard to a forest. R.-1iNK NATURAL 1 !QU?ALITY 1 to 3 !RANK LINKAGES This area would provide linkage to other areas in planned 3 10 to 1 (none, low & high) j developments to the north that have been proposed for dedication 'RANK FEATURES. 0 to 3 to the City, 1 4 1 I 5 TOTAL RANK 9 Prepared by Mike Reichenbacb TIGDr1Ta21995 Appendix C 1995 City'of Tigard Forest Areas Inventory Data Sheet Page 20 1 'NATURAL AREA 2 Ownership G-2 3 DATE of evaluation Private 4/29195 4 CATEGORY I VEGETATION TYPE Forested 5 upland or riparian conifer, mix. deciduous or shrub 6 CANOPY CLOSURE upland conifer closed. open, scattered COMMON TREE closed SPECIES Estimated number of 8 IDouglas-fir, trees per acre 'Estimated average size of 9 major tree species the size of the Douglas-fir varies from 14" to 40 plus inches 10 Estimated age of major ' tree species FOREST TYPE, abundant, j 60 to over 100 11 common, uncommon SUCCESSION uncommon in study area 12 very early, early mature, late or old growth 'Approx. Number of Acres mature 13► 14/PRESENT USE SITE VALUES forested 151 wildlife, trail, corridor I protection etc. OTHER COMMENTS wildlife, trails A streambed starts in the Southern portion of the property and 16. flows north creating a ravine along the Eastern boundary. The Northern end of the property slopes steeply to the floor of a larger drainage. Red ring rot was observed on in this area. 1 I R.�NIi NATURAL QUALITY 1 to 5 CRANK LINKAGES This area would provide linkage to other areas in planned 3 10 to 1 (none, low & high)g ) developments to the north that have been proposed for dedication NK FEATURES. 0 to 3 to the City .5 R 4 There are several Douglas-fir in excess of 3'on this property. 5 'TOTAL R. NIi These are estimated at over 100 years in age. 1 4.5 Prepared by Mike Reichenbach TIGD:1T.a2.995 Appendix C 1995 • Cityof Tigard Forest Areas Inventory Data Sheet Page 21 1 NATURAL AREA 2 (Ownership M-1 3 DATE of evaluation Private Viewed from the road and from the Davis property, 4/29/95 4 CATEGORY VEGETATION TYPE Forested 5 upland or riparian conifer, mix, deciduous or shrub 6 CANOPY"CLOSURE i Upland closed, open, scattered COMMON TREE i Scattered SPECIES 8 Estimated number of Douglas-fir trees per acre Estimated average size of uk 9 major tree species 10 ltreespeci mated age of majores FOREST TYPE, abundant, uk 11 common, uncommon SUCCESSION common 12 very early, early mature, late or old growth 13IApprox. Number of Acres early to mature 14 PRESENT USE (SITE VALUES unmanaged forestland 151 wildlife, trail, corridor protection etc. OTHER CObIIbIENTS wildlife, and forest The understory a 16; ppears to be of highquality. The propertyto the North was planted with Douglas-fir. These trees need to be released from competing vegetation. I recommend that the owner contact OSU Cooperative Extension Service. 1 I RANK NATURAL QUALITY" 1 to 5 (RANK LINKAGES3 3 !0 to 1 (none, low & high) ;RANK FEATURES, 0 to 3 0.5 4i 5 TOTAL RANI; 0 3.5 (est., no on-site visit) LS Prepared by Mike ReichenbachTIGDAT.1?.?t95 Appendix C 1995 City of Tigard Forest Areas Inventory Page 22 Data Sheet 1 !NATURAL AREA 2 !Ownership NA-7 3 I DATE of evaluation Private 4 CATEGORY 4/29/1995, viewed from Menlor Lane VEGETATION TYPE Forested 5 upland or riparian conifer, mix, deciduous or shrub 6 'CANOPY CLOSURE upland conifer, riparian closed, open, scattered COMMON TREE Scattered ! SPECIES Estimated number of red alder and Douglas fir 8 trees per acre 1Estimated average size of uk 9 major tree species 10'Estimated age of major I 18" for Douglas-Sr tree species FOREST TYPE, abundant, 11 common, uncommon SUCCESSION uncommon in study area 1 very early, early mature, late or r old growth 131 Approx. Number of Acres 14'PRESENT USE ISITE VALUES 151 wildlife, trail. corridor protection etc. !OTHER COMMENTS I 161 I i RANK NATURAL !QUALITY 1 to 5 RANK LINKAGES 2 3 10 to 1 (none, low & high) r RANK FEATURES, 0 to 3 0 4 ! 5 ITOTAL RANK0 2 (est., no onsite visit) Prepared by tilike Reichenbach TIGDr1T 1?. 5 Appendix C 1995 City of Tigard Forest Areas Inventory Data Sheet Page 23 1 'NATURAL AREA 2 Ownershi i P_1 3 DATE of evaluation i Private ®CATEGORY 4!22/95 VEGETATION TYPE Forested 5 upland or riparian conifer, mix. deciduous or shrub 6 CANOPY CLOSURE Upland conifer closed, open, scattered !COMMON TREE closed SPECIES Douglas fir, black cherry, big-leaf maple, red alder 8 Estimated number of i trees per acre 'Estimated average size of 250 to 300 9 major tree species range 8 to 26" 10 Estimated age of major 14" average tree species !FOREST TYPE, abundant, i 60 years 11 common, uncommon { uncommon in study area SUCCESSION 12 I very early, early mature, late or 1 old growth !Approx. Number of Acres early to mature 13I 14 PRESENT USE forested, the portion of this area closer to the residence has lawn ,SITE VALUES as an understory 151 wildlife, trail. corridor Iprotection etc. 'OTHER COMMENTS forest I 161 tree heights =80 - 90 feet (dominant 100- 110), probable previous harvest 40 or more years ago. 1 i RA K NATURAL, QU.ALITy 1 to 5 !RANK LINKAGES 2 3 I0 to 1 (none, low & high) RANK FEATURES. 0 to 3 1 I 4i 1 5 TOTAL RANK uncommon nature of conifer forest. 2 5 Prepared by Mike Reichenbach TIC D XLS Appendix C 1995 City of Tigard Forest Areas Inventory Data Sheet Page 24 !NATURAL AREA 2 'Ownershi P-2 3 (DATE of evaluation Private 4/29/1995, viewed from adjacent road right-of-way 4 (CATEGORY j VEGETATION TYPE Forested 5 upland or riparian conifer, mix, deciduous or shrub 6 'CANOPY CLOSURE Upland mix closed, open, scattered ICOIVIIIION TREE Closed f SPECIES 8 Estimated number of ++ Douglas-fir, bigleaf maple, and alder trees per acre Estimated average size ofuk 9 major tree species 10'Estimated age of major bigleaf maple and alder 8-14": Douglas-fir 10-16" and 60-80 feet tree species FOREST TYPE, abundant, tall 11 +common, uncommon SUCCESSION I common 12 very early, early mature, late or old growth IApprox- Number of Acres early, mature 131 14 PRESENT USE ilk ISITE VALUES i forest 15j wildlife, trail, corridor protection etc. wildlife, in close proximity to city owned property to the NE IOTHER COMMENTS 16! I � slopes to the East RANK NATURAL 1 !QUALITY 1 to 5 jRAcNK LINKAGES 3 3 I0 to 1 (none, low & high) RANK FE ATURES. 0 to 3 ! o 4I 5 TOT.-1L R ANK o 3 (est., no on-site visit) Prepared by Mike ReichenbachTIGDAT�?.995 Appendix C 1995 City of Tigard Forest Areas Inventory Data Sheet Page 25 I NATURAL AREA 2 IOwnershi. S-1 3 1DATE of evaluation i Private 4 'CATEGORY 4/22/95 VEGETATION TYPE Forested upland or riparian 5 conifer, mix, deciduous or shrub CANOPY CLOSURE 6 Riparian to Upland mix closed, open, scattered COMMON TREE closed SPECIES Estimated number of bigleaf maple and red alder 8 trees per acre Estimated average size of Douglas fir= 14 inches dbh and larger, 9 I major tree species big-leaf maple=4- 16 inches dbh, 10 Estimated age of major alder=6-14 inches tree species 'FOREST TYPE, abundant. 30 - 60 years 11 common, uncommon !SUCCESSION common 12 very early, early mature. late or old growth approx. Number of Acres 1 early 13I 14'PRESENT USE !SITE VALUES forest high connectivity between common property on adjacent 154 wildlife, trail, corridor protection etc. development and city property COMMENTS values (OTHER C0 i 4 16 I slopes to the Northwest, running water in the steep sided creek area, disturbance evident from installation of sewer line. 1 R:A.NK NATURAL QU.ALITY1to5 i RANK LINKAGES 2 3 10 to 1 (none. low & high) RANK FEATURES, 0 to 3 1 4 ; 5 'TOTAL RANI{ • 0 3 Prepared by Mike Reichenbach Appendix C TIGDAT.a2.lL 1995 Appendix D. Building with Trees Arboreal Enterprises City of Tigard. Inventory and Assessment of Forested Natural Areas on Bull Mountain June,95 Appendix D. Building with Trees Arboreal Enterprises City of Tigard. Inventory and Assessment of Forested Natural Areas on Bull Mountain September,95 BUILDING WITH TREES IN THE PACIFIC NORTHWEST Prepared By Michael R. Reichenbach, Arboreal Enterprises 4422 Norfolk Street, West Linn. Oregon 97068 (503)656-7835 August 11, 1994 Building with trees in the Pacific Northwest almost always involves attempts to preserve conifers, especially Douglas-fir. p PRESERVING CONIFERS The preservation of individual trees during the development of coniferous forested sites in the Pacific Northwest is often difficult at best. Mature close canopy stands of coniferous trees have adapted toa d d and do not readily adapt to changes. Plan to set aside large areasfor thestn retention of groups of trees rather than try to retain individual mature specimens. Small groups of trees in young, (< 30 yrs.), healthy stands of Douglas-fir can often be preserved. In any case, effort must be made to protect the root system. The root system can be damaged by cutting, s lite as 1") crushing, or compacting. Damage to 50% or more of thee root syg (even stemtlis almost always a cause to remove the tree. The development process often damages roots, changes drainage, increases light intensities, raises soil temperatures, and increases exposure to winds. These factors create conditions that can lead to the decline or failure of trees. After development, increases in the amount and duration of irrigation and the types of ground cover may also create conditions that cause trees to fail or decline and die. To reduce the risks associated with tree failure in coniferous trees insect and remove trees found with the following defects: p • Less than 50% live crown; • Multiple tops, forks, splits, or co-dominant stems; • Broken or missing tops; • Damage to more than 50% of the root system; • Evidence of red ring rot, laminated root rot, or other decay organisms; and • Recent exposure to increased winds through the removal of adjacent trees. All trees should be inspected for defects before, during and after development. Successful tree preservation will depend on planning the development, coordinating construction, and providin avoids dama�- g ongoing maintenance that 1) ,e to the tree and its roots; 2) reduces dramatic and sudden changes in light intensity, and moisture; and 3) avoids exposing trees to increased winds. The table, Trees of the Pacific Northwest and Their Page 1 Michael R.Reichenbach,Arboreal Enterprises August I1, 1994 Adaptability to Development, which species can be retained and how tobeginplel anning their des some eneral ir r as to retention. Trees of the Pacific Northwest and Their Adaptability to Develo ment Common name What to Keep big leaf maple Mature big leaf maples are generally not well suited for retention. Acer macrophyllum Keep only young, rapidly growing trees with single stems and well- formed crowns. Damage to the trunk and root crown will lead to decay, and reduce the service life of the tree. Douglas-fir In general, Douglas-fir does not withstand even minor damage to the Psuedotsuga men,-iesii root crown and root system. Such damage can cause the tree to decline and die in as little as two years. Retain rapidly growing groves of trees or small groups of trees that have no defects, that have well-tapered trunks, and that have live limbs over at least 50%of their height. Defects include sweep, lean, multiple tops, missing or broken tops, trunk scars, fungal growths or growth habit not characteristic of the species. Young(<30 growing are more likely to recover from compaction, crushing d shallowees fill over the root systems. However, even shallow fill over 50%of the root system can cause Douglas-fir to decline and die. Trees to be retained should be evaluated prior, during and after construction for their ability to withstand increased exposure to wind without increased risk of failure. Retaining groves generally reduces the risk of breakage or windthrow. On well drained, thick soils this species is less prone to windthrow and more tolerant of root damage. Oregon white This species has preservation potential and generally withstands root oak damage, other than root cutting, better than Douglas-fir. There is Quercus garryana potential for Armillaria root rot to infect cut or crushed roots of trees, especially those growing on wet soils. Avoid chap rapidly changing the amount and duration of irrigationhng tep draell e or drained soils, especially soils over river cobble the structural and fine root system of this tree may be found deeper than 18". Preservation of single mature specimens requires protecting the root system. red alder This short-lived tree, relative to oak and Douglas-fir, is generally not .4lnus rubra well suited for retention. Damage to the roots, root crown and trunk will lead to decay and reduce the life of the tree. If red alder is to be retained, try to retain groves rather than single specimens. vine maple This species may have preservation potential. Avoid sudden changes Acer circinatum in light intensity. Shaded trees should remain shaded. western This species may have preservation potential. Select rapidly growing dogwood trees with no defect. Cornus nuttallii Page Michael R. Reichenbach.Arboreal Enterprises August 11. 1994 Trees of the Pacific Northwest and Their Adaptability to Development, continued Common What to Keep name western This species is not tolerant of even minor damage to the trunk, root hemlock crown or major roots. Damage usually leads to decay and future Tauga heterophylla failure. western red Western red cedar has the potential to remain viable as a landscape cedar tree following clearing and development. However, it should be Thuja plicata evaluated for its ability to withstand increased winds. This species generally has a shallow root system and windthrow is more common than breakage. Trees on well drained sites will generally survive construction better than trees on poorly drained sites. SUMMARY SPACE. Plan to leave and protect the root area around each tree or grove during construction and plan to maintain the trees and the area around the trees after construction. Mature trees often decline and die from changes in drainage and excess irrigation after construction. FOCUS ON GROVES. Trees that have developed as part of a forest should be retained as groves. Preserving individual coniferous trees that were a part of a forest often leads to breakage or windthrow. YOUNG, HEALTHY TREES. Tree preservation projects are often more successful if young, healthy trees can be targeted for retention. Mature trees are not able to respond to changes in their environment as quickly as young trees. Page 3 Michael R.Reichenbach,Arboreal Enterprises August 11. 1994 Appendix E. Map Arboreal Enterprises City of Tigard,Inventory and Assessment of Forested Natural Areas on Bull Mountain June,95 Appendix E. Map Arboreal Enterprises City of Tigard.Inventory and Assessment of Forested Natural Areas on Bull Mountain September.95 s.7" 7A ,..--.•-•--. •\ '.'-., ••.'''.. / '••,.,.', -„,..\--,_-• ".1—.___;j _ .. \ • ‹, '" :' I----- 1'' ". \ LU LU , • I—I > ___il 1----L_,,L1.-_-lj 7- /------,-. ! ! 1 ,,---",: \>•\,,- ---- s.. „,I . _ ,------I--...T . Et_ I , --; I I --,-. } --, I— fi_i/ :-----1----.....j4) j. i _J I i ' ' \Y" .›. - . -,..-a ' r-1 II • , r. • ..._, 1 ,!---7-:: / ....4.........t.1 . t----i .......C.,/ .=7._ I , -r----,•. , / / ! k - / / It ..--.--:--... • A\ ', / ; ,,,.. ! ! - i___-----' ;-----r---- ..-----, (___ L _,_1 1 ...-/ t i " -..- -7= ( l " ''-ke'D- v---. --: <,, ''\,77-)%1.> • /\...‘ '''' ''././ '''' /f('`,..1_\__// ----''- ---, I , ' - 1,d'ri'-V.'.' 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