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HomeMy WebLinkAboutArborist Report_1. . . . . . . . . . . . . . . . . . . . . . . . . . February 14th, 2012 Ms. Tiffiny Brown Burnstead Construction Co. 11980 NE 24th ST, Suite 200 Bellevue, WA 98005 Dear Mr. Brown: At your request, I have completed an assessment of the significant trees on the Maplewood Park East project site in Renton. The former address of the site is 15240 SE 132nd ST. My assignment is to evaluate the condition of the subject trees and report on my findings. The purpose of the report is to identify non-viable, high-risk trees that should not be retained during the development of the site. A large component of the trees at the site is comprised of red alder and black cottonwood trees. Renton Code RMC 4-4-130 H7 Tree/Ground Cover Retention allows for the removal of these species due to weak wood which is prone to breakage. When performing the condition assessment, these species were ignored. However, it was noted that a large percentage of the red alder that was surveyed is dead or in serious decline. Big leaf maple also makes up a large percentage of species composition at the site. Unfortunately, the majority has developed very poor trunk taper and form. These are young trees, estimated at less than 30 years of age and already have multiple structural defects which include broken tops, major crooks, and forked tops with codominant (equal diameter) stems. Very few of the maple trees make good candidates for retention on a developed site. They all have a very high height to diameter ratio and are very prone to stem breakage during wind or ice/snow loads. They have developed very poor taper due to intense competition with adjacent trees for sunlight. A Tree Map is attached and part of this report. The map indicates the location of non-viable, high-risk trees, which are shaded in “red”. A total of 29 trees were found to be in a non- viable condition, mainly due to compromising structural defects. A Tree Condition Summary Sheet is attached which provides specific tree information. The tree numbers correspond with the tag numbers found in the field. The tags on trees numbered #101 through #109 could not be found during the assessment. These trees can be identified in the field by a numbered piece of blue flagging tied near it. Red alder and black cottonwood trees are shaded in “orange” on the tree map. There are several high-risk cottonwood trees in the right-of-way of SE 132nd Street, many of which are completely dead. These are shaded in “blue” and should be removed from the site as soon as feasibly possible. For a Forester Every Day is Earth Day February 10th, 2012 Page 2 INTERNATIONAL FORESTRY CONSULTANTS, INC. Methodology The tree assessment procedure involves the examination of many factors: • The crown of the tree is examined for current vigor. This is comprised of inspecting the crown (foliage, buds and branches) for color, density, form, and annual shoot growth, limb dieback and disease. • The bole or main stem of the tree is inspected for decay, which includes cavities, wounds, fruiting bodies of decay (conks or mushrooms), seams, insects, bleeding, callus development, broken or dead tops, structural defects and unnatural leans. Structural defects include crooks, forks with V-shaped crotches, multiple attachments, and excessive sweep. • The root collar and roots are inspected for the presence of decay, insects and/or damage, as well as if they have been injured, undermined or exposed, or original grade has been altered. Inspection methods included examining the trees with binoculars and sounding the trunks with a mallet. No invasive measures were used to assess tree conditions. Based on these factors a determination of viability is made. Trees considered not viable are trees that are in a poor condition due to disease, extensive decay and/or cumulative structural defects, which exacerbate failure potential. A “viable” tree is a tree found to be in good health, in a sound condition with minimal defects and is suitable for its location. Also, it will be wind firm if isolated or left as part of a grouping or grove of trees. Findings A Tree Condition Summary Sheet is attached which provides specific tree information. This sheet indicates species, size, height to diameter ratio and specific defects. Tree condition is scored based on an array of factors. All trees listed in the summary sheets are considered non-viable. The majority of the big leaf maple trees are not suitable for retention on a developed site. The development of very poor trunk taper (height to diameter ratios) is high. Isolating these trees or removing clusters of trees adjacent to them will subject them to stem breakage and top failure. 90% of them have a significant crook in the lower trunk from past top failures. The bitter cherry also has developed poor taper similar to the maple. The red alder trees at the site are in poor condition. Many of the surveyed trees are presently dead and/or in vast decline. Discussion Although I did not report on every big leaf maple tree at the site, I consider 90% of them to be non-viable for reasons discussed above. The subjects are simply too tall and skinny to ever develop into structurally sound trees. February 10th, 2012 Page 3 INTERNATIONAL FORESTRY CONSULTANTS, INC. As indicated in the Renton Code, the alder and cottonwood trees should be removed from the site. These species are not suitable for retention on developed sites. The western hemlock trees at the site are also not the best candidates for retention either. Two large hemlock trees at the front of the property were wind-thrown in recent years, indicating a root rot issue. Two others (#7370 and #7676) at the front of the property have developed extensive internal stem decay from past top and codominant stem failures; and are considered non-viable. The Douglas-fir trees at the site are the best candidates for retention. These appear structurally sound, wind firm, and in good health. There is no warranty suggested for any of the trees subject to this report. Weather, latent tree conditions, and future man-caused activities could cause physiologic changes and deteriorating tree condition. Over time, deteriorating tree conditions may appear and there may be conditions, which are not now visible which, could cause tree failure. This report or the verbal comments made at the site in no way warrant the structural stability or long term condition of any tree, but represent my opinion based on the observations made. Nearly all trees in any condition standing within reach of improvements or human use areas represent hazards that could lead to damage or injury. Please call if I can be of further assistance. Sincerely, Bob Layton ISA Certified Arborist #PN-2714A Certified Tree Risk Assessor #233 February 10th, 2012 Page 4 INTERNATIONAL FORESTRY CONSULTANTS, INC. Typical structure of big leaf maple at site, poorly tapered stems, crooks and forks Codominant stem failure of tree #7500, trunk splitting February 10th, 2012 Page 5 INTERNATIONAL FORESTRY CONSULTANTS, INC. Tree development from stump sprouts, stems are tightly spaced, high risk of splitting off Large cluster on rotten base, high risk for breaking off as stems increase in girth and height 1 TREE CONDITION SUMMARY International Forestry Consultants Date:2/8/2012 Redwood Acres For: Maplewood Park East 15240 SE 132nd ST Inspector:Layton Renton Crown Bole Roots Tree #RecommendationPriorityConditionSpeciesNative/PlantedDIA.HeightH/DDriplineGreen %LimbTipsAsymmetricColorDecayIncluded BarkSeams-PitchingBroken - Topped -SproutsCrook-Fork-sweepLeanDecayExposedSeveredComments N S E W 7346 17 big leaf maple N 27 56 25 3 4 5 5 broken and rotten 7351 10 big leaf maple N 12 53 53 2 4 1 3 heavy lean, poor structure 7330 15 big leaf maple N 15 73 58 2 2 2 3 3 3 clump of 5-15",11",10",7",6" 7331 14 big leaf maple N 22 70 38 2 3 5 4 2 - 11" stems, poor structure 7275 13 Douglas-fir N 23 84 44 5 5 3 dead tree, hung up on adjacent tree 101 19 big leaf maple N 10 72 86 2 3 3 3 4 4 clump of 3 stems - 10" 9" 8", poor structure 102 17 big leaf maple N 13 75 69 2 4 1 2 1 4 3 structural defects, poor form 103 13 big leaf maple N 10 83 100 2 1 4 1 1 4 tight clump of 10 stems - 5" to 10" 7423 14 cherry N 8 73 110 3 2 4 2 3 in natural decline 104 11 big leaf maple N 12 81 81 1 2 1 3 4 major crook forked top 7416 13 cherry N 9 71 95 3 1 1 4 4 heavy lean in natural decline 105 10 big leaf maple N 13 83 77 1 1 4 4 fork at 3' 13" 11" codom 7413 13 big leaf maple N 13 74 68 2 3 4 1 3 cavity, forked tops, poor structure 7395 14 big leaf maple N 11 42 46 1 4 3 3 3 problematic lean, poor structure 106 9 big leaf maple N 11 65 71 1 1 3 4 clump of 4 - 6" to 11" 107 10 big leaf maple N 10 48 58 1 5 4 clump of 10 stems - 6" to 10" 108 10 big leaf maple N 12 46 46 1 1 4 4 fork - codominant stems 7370 11 western hemlock N 24 98 49 1 1 4 1 4 significant decay at 20' at crook, past failure 7378 13 big leaf maple N 13 56 52 2 2 2 2 3 2 2 stems - 13",12" bulge and seam 7676 17 western hemlock N 26 38 18 4 4 4 5 broken, dead top Recommendation Crown %Condition Score Priority Condition Code X Remove 0 No Action 5 0%5 severe 1 Immediate 11 - +Poor RD Remove Defect CC Crown Clean 4 10-20%4 poor 2 Six Months 5 - 10 Fair-Monitor DW Remove Dead wood RC Raise Canopy 3 20-40%3 moderate 3 1 year +0 - 4 Good EW Remove End Weight CR Reduce Canopy 2 40-60%2 fair M Monitor-Re-evaluate in 1-2 years 1 60-70%1 noted H/D = height/diameter ratio > 50 potentially hazardous 0 70%+ Green % for evergreen species only 1 TREE CONDITION SUMMARY International Forestry Consultants Date:2/8/2012 Redwood Acres For: Maplewood Park East 15240 SE 132nd ST Inspector:Layton Renton Crown Bole Roots Tree #RecommendationPriorityConditionSpeciesNative/PlantedDIA.HeightH/DDriplineGreen %LimbTipsAsymmetricColorDecayIncluded BarkSeams-PitchingBroken - Topped -SproutsCrook-Fork-sweepLeanDecayExposedSeveredComments N S E W 7672 14 big leaf maple N 14 61 52 2 2 3 2 1 4 clump of 4 6 to 14." poor structure 7663 12 big leaf maple N 18 85 57 1 4 2 4 1 clump of 2-18",15" rotten bases 7667 11 western red cedar N 38 97 31 1 2 4 4 fork at 36' - 3 tops, high risk for breakage 7525 12 big leaf maple N 19 52 33 2 1 2 5 2 broken main leader, structure compromised 7523 9 big leaf maple N 10 44 53 2 1 1 5 broken top, structure compromised 7500 15 big leaf maple N 16 66 50 2 3 5 5 codominant stems, trunk splitting, extreme risk 7600 13 big leaf maple N 19 20 13 4 4 5 broken at 20', complete failure 109 10 western hemlock N 7 22 38 5 5 recent dead tree 7635 18 big leaf maple N 20 76 46 3 4 4 4 3 clump of 8 stems-7 are 6" to 10" and one 20", r Recommendation Crown %Condition Score Priority Condition Code X Remove 0 No Action 5 0%5 severe 1 Immediate 11 - +Poor RD Remove Defect CC Crown Clean 4 10-20%4 poor 2 Six Months 5 - 10 Fair-Monitor DW Remove Dead wood RC Raise Canopy 3 20-40%3 moderate 3 1 year +0 - 4 Good EW Remove End Weight CR Reduce Canopy 2 40-60%2 fair M Monitor-Re-evaluate in 1-2 years 1 60-70%1 noted H/D = height/diameter ratio > 50 potentially hazardous 0 70%+ Green % for evergreen species only