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HomeMy WebLinkAboutFile Documents.634 W Hopkins Ave.0106-2021-BRES (33) 634 W. Hopkins Avenue Aspen, CO Tree Survey Report Prepared By: Chris Forman ISA Board Certified Master Arborist #RM-2352BM November 19, 2020 15450 Hwy 82, Carbondale CO 81623 (970) 963-3070 1 | Page PURPOSE & SUMMARY The following report pertains to the property located at 634 West Hopkins Avenue, within the city limits of Aspen, Colorado. There are numerous trees on this site within the landscaped area surrounding the home, of which 15 are large enough to be governed by the City of Aspen Municipal Code Language. 7 of these trees are located within the City Right of Way (ROW) on the west side of the property along 6th Street. Tree species within the landscaped areas consist of aspen (Populus tremuloides), blue spruce (Picea pungens), and narrowleaf cottonwood (Populus angustifolia). Aluminum numbered tags (#1-9) were placed on the lower trunks of these trees in order to provide clarity to the inventory findings. No tags were placed on the trees found within the ROW though they were assessed and included in this assignment as trees A through H. This report is designed to identify trees within the landscaped area and provide individual analysis of those trees. Individual tree analysis included species type, tree diameter at breast height (DBH), overall condition, and maximum value as assigned by the City of Aspen Municipal Code. The report will summarize the findings within the landscape area of the property. One of the trees located within the landscaped area scored a ‘good’ condition. There are 8 trees within the property boundaries that are in fair or poor condition, and another 6 scoring the same rating found within the adjacent ROW. If the owners of 634 W. Hopkins are considering any management activities for the right of way trees, a meeting with the City Forester must be scheduled to obtain his feedback. METHODOLOGY ASSIGNMENT Aspen Tree Service has been asked by the property owner’s representative, Lift Studio LLC, to inventory and assess all of the landscape trees and provide a report on their condition. In addition, the assignment included placing numbered aluminum tags on the code sized trees found throughout the property. LIMITS OF THE ASSIGNMENT This investigation is based solely upon the information noted from visits to the site in October 2020. I have not performed any professional surveying, laboratory examinations, soil composition/compaction studies, or any other diagnostic techniques beyond ground level visual examination of the trees and the site. At the time of my site visit, there were 3-5 inches of snow on the ground. I developed general conclusions of tree health and have provided a summary based upon these observations. PURPOSE & USE OF REPORT The purpose of this report is to provide current information regarding the landscape trees within the property boundaries as well as the trees in the ROW. It is intended to be used by the property owner as an informative reference for developing a management strategy for the tree resources on the property. 2 | Page INVENTORY Aspen Tree Service completed an inventory of landscape trees on this property in October of 2020 and tagged each tree stem with numbered aluminum tags. The numbers on the tags correspond to the tree numbers assigned on the tree inventory table found as Attachment A of this report. Trees within the ROW were not tagged, but are defined in this inventory as trees A-H and are shown on the attached map as Attachment B. For purposes of this report, a tree stem is defined as a stem originating at the ground or attached with another stem within 4 ½ feet from the ground. During the inventory process, each tree stem within the scope of this report was measured with a diameter tape and visually evaluated from the ground. Tree data was collected for each stem including, tree #, the Diameter at Breast Height (DBH) measured to the lower ½ inch at approximately 4.5 feet above ground level, tree species, and condition. Individual trees were inspected from ground level only. No advanced assessment was done in tree canopies or below existing soil levels. Condition values were assigned as a result of visual indicators such as the presence of dead limbs, signs or symptoms of disease/insects, or structural defects. Definitions of the condition scale are as follows: Excellent - A healthy, vigorous tree, reasonably free of signs and symptoms of disease, with good structure and form typical of the species. Good - Tree with slight decline in vigor, small amount of twig dieback, minor structural defects that could be corrected. Fair - Tree with moderate vigor, moderate twig and small branch dieback, thinning of crown, poor leaf color, moderate structural defects that might be mitigated by regular care. Poor - Tree in decline, epicormic growth, extensive dieback of medium to large branches, significant pathogen activity or structural defects that cannot be abated. Very Poor/Dead - Tree is in severe decline, highly hazardous or is dead. MITIGATION CALCULATION Even though the purpose of this inventory report does not include applying for a tree removal permit with the City of Aspen, a discussion regarding mitigation should be considered. We understand the purpose and objectives of the City’s Tree Removal and Mitigation requirements. Healthy trees are an asset to the property owner and the community. However, trees that are in poor health or structurally defected can present a safety and forest health liability for the property owner and the community. Therefore, we believe it is reasonable and appropriate to account for this liability by adjusting/devaluing the mitigation value of a specific tree based on the condition of the tree. This adjustment is made by multiplying the tree’s value per the City of Aspen Municipal Code Valuation Formula by a percentage based on the tree condition. The result is an adjusted mitigation value. The following narrative details our mitigation adjustment procedure. Final tree approvals and mitigation values are ultimately made by the City Forester or his designee. All decisions regarding management of the trees within the ROW are made by the City Forester or his designee. 3 | Page Each tree stem evaluated was entered into a tree inventory worksheet noting the tree#, DBH, condition rating, comments, and the adjusted mitigation DBH. The table showing these figures can be found below in the ‘Tree Inventory Table’ section of this document. The adjusted mitigation DBH was calculated by multiplying the actual mitigation value by the assigned mitigation percentage. The mitigation adjustment percentage ranges from 0 to 100%. This percentage was assigned based on the condition of the tree, forest health and the wildfire risk the tree poses to the site and area. Structurally defective trees can present a safety risk to people and/or property. Dead or declining trees pose a threat to forest health, hosting and attracting insect pests and disease becoming a point source for the spread of these pest and disease problems. Dead and declining trees can also provide a fuel source for wildfire and if they are tall, provide a mechanism for the spread of a wildfire. The following are the mitigation adjustment percentages used to quantify all of these risks. We believe this a reasonable method to maintain the City’s tree removal mitigation objectives while achieving an appropriate and sustainable planting plan. Adjusted mitigation numbers can benefit the community forest by encouraging proper species, planting numbers, sizes, and spacing for site conditions, resulting in a long-term asset for everyone involved. 1. 100% Mitigation – A tree scoring an Excellent or Good Condition Rating. 2. 50% Mitigation – A tree scoring a Fair Condition Rating. 3. 0% Mitigation – A dead tree or scoring a Poor or Very Poor Condition Rating. OBSERVATIONS & DISCUSSION SITE DESCRIPTION 634 West Hopkins Avenue is a residential property in the west end of Aspen, populated with narrowleaf cottonwood, aspen, and spruce throughout the site. The property has manicured landscaped areas and turfgrass on a relatively flat topography. TREE OBSERVATIONS All of the landscape area trees evaluated in this report have diameters of 5 inches are greater. Each tree was evaluated visually and entered into the attached tree inventory worksheet. This worksheet contains the tree species, condition, comments, and maximum mitigation value based on the City of Aspen tree removal code language. Trees below 5 inches in DBH were not included in the analysis. The following information pertains to the tree observations acquired in the field during the inventory process. Many of the aspen trees and cottonwood trees on the site have a codominant growth structure originating at grade level. This type of growth occurs when 2 or more stems originate from a single point of origin, or when 2 or more stems originate at grade level in close proximity to one another. Over time, these stems increase in size and fill the space that previously existed between the stems to create what is known as bark inclusions. When this happens, competing forces are exerted on the 4 | Page codominant stems and can lead to structural failure of one or more stems. Failure is not a certainty, though the likelihood of failure in these species of trees with codominant structure increases under snow and wind loading. Overcrowding of trees in the ROW has resulted in some of these trees competing for resources such as light, water, and nutrients. Due to this competition, specifically for light, several trees have developed asymmetrical canopies and branch structures atypical for the species. Poor canopy structure can increase the likelihood of failure under normal wind and snow loading. Competition for resources can also cause stress within individual trees and leave them prone to secondary insect and disease pathogens. Insect activity is present within the trees surveyed, though populations and severity vary throughout the landscape. Signs of aphid activity were noted in most of the aspen and cottonwood trees on site, as evidenced by the amount of black sooty mold on their branches and trunks. Sooty mold is a strong indicator of aphid activity, due to the mold feeding on the sticky secretions of aphids feeding on the leaves of the aspens. These insects can be problematic for the health and aesthetics of the aspen and cottonwood trees, but current population levels are not high enough to be a cause for concern. Wounding and internal decay were noted in several aspens. As the internal decay advances, the tree loses structural integrity. The loss of integrity increases the likelihood of whole tree or stem failure during wind and snow loading events. Several trees on the property are growing into the roofline and deck of the home. These trees are liabilities in the landscape and will not fully mature due to their location. Structural damage to the home is occurring currently due to the location of these trees and the issue will continue to worsen as the trees grow in height and girth. Girdling roots were noted at the base of a few cottonwood trees in the ROW. The existence of girdling roots can negatively impact trees’ structural integrity and overall health. Girdling roots are lateral roots that cut into other structural roots or into the actual trunk of the tree. The result of this growth pattern can make trees unstable or their overall health can decline because the girdling root(s) have damaged the vascular system of the tree. DISCUSSION The following information pertains to individual trees identified to have conditions that lend themselves to a reduction in mitigation value. All other trees within the scope of this report can be found within the tree inventory table and have condition ratings of ‘good’. Trees #1, 2, and 5 are aspens in poor condition. They all have advanced pockets of internal decay, negatively impacting their structural integrity. Trees #4, 6, 7, and 9 are aspen and spruce trees in poor condition. These trees are growing within close proximity of the home and several are already causing damage to the home. 5 | Page Tree #3 is an aspen tree in fair condition. The tree has a codominant growth form originating at the base as well as an asymmetric crown due to overcrowding. ROW tree A is a narrowleaf cottonwood tree in poor condition. This tree has 3 codominant stems originating at grade level with significant bark inclusions. In addition, 2 of the stems have developed a very poor canopy structure due to over competition in the crown of the tree. ROW tree C is a narrowleaf cottonwood tree in fair condition. This tree has a codominant growth habit the developed within the canopy at approximately 20’ above grade. There does not appear to be significant bark inclusion, as evidenced by the ‘U’ shaped crotch. This type of growth habit reduces the likelihood of failure at the point of codominance. It remains a structural defect, therefore a fair rating was assigned. ROW tree D is a blue spruce in poor condition. This tree’s top has been damaged/broken out in years past. The formation of multiple leads in the top 15’ feet of the tree is indicative of this type of damage in spruce. It is growing within the understory of mature cottonwoods as well. The tree will never fully mature in the landscape and portions of its top will continue to fail under snow loading as it has in the past. ROW trees E, F, and G are all narrowleaf cottonwoods in fair condition. Trees E and G have codominant stems at grade level with bark inclusion. The growth habit of these trees is very upright, helping to mitigate the forces placed on these areas of codominance. Tree F has developed a significant girdling root at its base. The tree has a higher likelihood of failure under normal wind and snow loading and may also decline in overall health due to the girdling root impacting uptake of water and nutrient. 6 | Page PHOTOS Photo 1. Tree #1 w/ old trunk wounding and internal decay 7 | Page Photo 2. Tree #2 w/ old trunk wounding and internal decay 8 | Page Photo 3. Tree #4 growing under/into deck of house 9 | Page Photo 4. Tree #5 with codominant form and decay at base 10 | Page Photo 5. Tree #6 growing into the roofline by front door 11 | Page Photo 6. Tree #7 growing over house; overcrowded by adjacent cottonwood 12 | Page CONCLUSIONS One of the trees located within the landscaped area scored a ‘good’ condition, tree #8. On the other hand, several of the trees in fair or poor condition have structural defects, poor canopy and/or root development, are damaging the home, or are generally overcrowded. Trees showing these conditions will continue to be liabilities in the landscape and action should be taken to ensure the trees do not progress to a point where they are a hazard to the property or the adjacent ROW. There are 7 trees on site that are in fair or poor condition and another 6 scoring the same rating found within the adjacent ROW. RECOMMENDATIONS I recommend removing the trees listed in poor condition found within the property boundaries of 634 W. Hopkins Avenue. The trees in fair condition could be considered for removal based upon the property owner’s goals and risk level tolerance. The trees within the ROW are the responsibility of the City of Aspen Parks Department Forester. If the owners of 634 W. Hopkins are considering any management activities for these trees, based upon their future goals of the property or current concerns over tree conditions, a meeting with the City Forester must be scheduled to obtain his feedback. 634 W. Hopkins Avenue Tree Inventory Aspen Tree Service November, 2020 Survey ID Tag ID#Species # of Stems DBH Mitigation Value Suggested Mitigation Value Condition Comments T19 1 Aspen 1 15.5 $ 8,486.83 $ - Poor Wound @ base; internal decay T21 2 Aspen 1 7.5 1,987.03$ $ - Poor Wound @ base; internal decay T22/23 3 Aspen 2 5, 8 $ 3,143.92 $ 1,571.96 Fair Asymmetric crown; codominant at base T25 4 Blue spruce 1 6 1,271.70$ $ - Poor Growing under/into deck; no future T1/2 5 Aspen 2 8.5, 10.5 6,446.81$ $ - Poor Codominant at base w/ decay in both stems at base T8 6 Blue spruce 1 7 1,730.92$ -$ Poor Growing into house at front door T10 7 Aspen 1 12 $ 5,086.80 -$ Poor Growing over house 6" from roofline; asymmetric due to over competition T11 8 Aspen 1 13 $ 5,969.92 $ 5,969.92 Good T18 9 Blue spruce 1 5 $ 883.12 $ - Poor Close to home; sparse canopy T3/4/5 A Narrowleaf cottonwood 3 10,15.5,18 $ 23,464.63 $ - Poor 3 codominant stems @ base w/ bark inclusion; poor canopy structure T6 B Narrowleaf cottonwood 1 46 $ 74,747.70 $ 74,747.70 Good T7 C Narrowleaf cottonwood 1 18.5 $ 12,089.98 $ 6,044.99 Fair Codominant @ 20' T9 D Blue spruce 1 12 5,086.80$ -$ Poor Multiple tops; old wounding; over crowded above T12/13/14 E Narrowleaf cottonwood 3 12,25,27.5 53,879.45$ $ 26,939.73 Fair Codominant stems @ base T15 F Narrowleaf cottonwood 1 20.5 14,845.33$ $ 7,422.67 Fair Girdling root(s) T16/17 G Narrowleaf cottonwood 2 13,25 28,048.04$ $ 14,024.02 Fair Codominant @ base; asymmetric crown T24 H Blue spruce 1 6 1,271.70$ 1,271.70$ Good Page 1of 1 Attachment A 1,128 188.1 Legend 1: WGS_1984_Web_Mercator_Auxiliary_Sphere Feet0188.194.04 Notes 634 W Hopkins Trees THIS MAP IS FOR INFORMATIONAL PURPOSES. Pitkin County GIS makes no warranty or guarantee concerning the completeness, accuracy, or reliability of the content represented. Map Created on 8:58 AM 11/19/20 at http://www.pitkinmapsandmore.com State Highway Road Centerline 4K Primary Road Secondary Road Service Road Attachment B