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HomeMy WebLinkAboutArborist Report 961804001 Vegetation Management Lisa Volkert 142 North Maple Street Port Hadlock WA Richard R Hefley – Consulting Arborist PO Box 177, 101 Reinier Road Nordland WA Page 2 of 21 Richard R. Hefley – Consulting Arborist – 360-385-2921 – rkhefley@olypen.com Vegetation Management Client: Lisa Volkert 142 North Maple Street Port Hadlock WA Author: Richard R Hefley Consulting Arborist Site Visit Date : 11/01/2020 Report Date : 11/13/2020 OBJECTIVES: Assess trees and vegetation growing on slope east of 142 North maple Street lot in Port Hadlock for vegetation management. Provide a plan to preserve view corridor with minimal impacts to slope. BACKGROUND I was contacted by Lisa Volkert by phone on 10/26/2020. She had recently purchased the lot at 142 North Maple Street, Port Hadlock, and wished to manage vegetation on the slope running east of the property. I examined the lot and adjoining slope on 11/01/2020. I traversed the face of the slope, noting vegetation types of trees and groundcovers. I prepared a report of my observations and recommendations on 11/13/2020. Page 3 of 21 Richard R. Hefley – Consulting Arborist – 360-385-2921 – rkhefley@olypen.com CONTENTS: Page 04 ………. Executive Summary Page 05 ………. Aerial Photo Page 06 ………. Views From Lot level Pages 07-08 … Mid-Slope – Multi-Trunked maples Page 09 ………. Blocked View From Lot ; Standard Bigleaf Maple Page 10 ………. Mid-Slope Sword Ferns Pages 11-12 … Lower Slope Pages 13-15 … Discussion and Recommendations ; Noxious Weed Notes Page 16 ………. Waiver of Liability ; Contact Information Page 17 ………. Appendices Page 4 of 21 Richard R. Hefley – Consulting Arborist – 360-385-2921 – rkhefley@olypen.com EXECUTIVE SUMMARY: I was contacted by Lisa Volkert and asked to examine her lot at 142 North maple Street, Port Hadlock, and make recommendations for managing the vegetation on and near a slope on the eastern border of the property. The slope is approximately 150’ in length and 80’ in height. It is primarily covered with Bigleaf Maple trees which have all been cut at one time and have since regrown into multiple-trunked trees. There is also a clump of Bitter Cherry trees near the crest of the slope. These have also been cut back prior to this date and have regrown with multiple trunks. There is one Western Red Cedar on this slope, and other than Sword Ferns, there is no other evergreen vegetation. After examining this lot and slope it is my conclusion that all the ecosystems will benefit from a systematic pruning of the deciduous trees and replanting areas with native evergreen groundcovers and trees. Dense deciduous trees like Bigleaf Maples are not effective at mitigating stormwater and have the added detriment of shading out plants to grow beneath them. One quarter of the trees may be re-cut back to their stumps, as has been performed on these trees before. The remaining 3/4s may have their crowns thinned or reduced by 25%. This practice may be repeated as needed on a yearly basis. Bigleaf Maples will regrow from hard pruning, as is amply demonstrated by all the Maple trees on this slope. The larger removed trunks should be anchored between trees on the slope to provide terraces for planting, left in the water to provide food and habitat for maritime life, and chipped and spread into the buffer area and/or the slope to serve as mulch and compost. Non-functional brush should not be left to accumulate on these slopes in order to mitigate potential fire dangers. Pruning should take place when slopes are dry, typically June through October. Following the pruning of the trees, the areas formerly covered by the canopies of the hard-pruned trees (those re-cut back to the stump) should be replanted with a combination of native evergreen groundcovers and small native evergreen tree seedlings. Evergreens are critical for mitigating stormwater damages during our wet winter seasons (the deciduous Maples do little). I recommend Sword Fern as the best groundcover, and Shore Pine and/or Pacific Yew as small evergreen trees, though there are many other varieties to choose from. I also recommend the buffer area between the crest of the bluff and development be planted using low evergreens such as the Sword Fern to grow up with and amid the Nootka Roses currently springing up in this area. The buffer zone and slope could be even further helped by the addition of Rain Gardens to interdict stormwater and reintroduce it into the water table if these are placed between the residence and the buffer zone. Periodic pruning, planting, and maintenance will vastly improve the management of stormwater and erosion, as well as maintaining the view corridor of this property. I did observe Himalayan Blackberry in small amounts at the crest of the slope, and a large clump at the toe of the slope. This is a noxious weed that should be mitigated where encountered. More information is available at https://www.co.jefferson.wa.us/195/Noxious-Weed-Control-Board. Page 5 of 21 Richard R. Hefley – Consulting Arborist – 360-385-2921 – rkhefley@olypen.com OBSERVATIONS: Aerial Photo The aerial photo shows the location of the major vegetation types on the slope from the crest to the toe. The vast majority of the slope is covered by Bigleaf Maples (Acer macrophyllum), trees which do very little to mitigate the damages of stormwater in the winter months when the majority of our rain occurs and these trees are leafless. Page 6 of 21 Richard R. Hefley – Consulting Arborist – 360-385-2921 – rkhefley@olypen.com OBSERVATIONS: Views from the lot – Above - Looking east – the southern half of the lot. Below – Looking east – northern half of the lot. Bitter Cherry clump. Multi-trunked Bigleaf maples. Nootka Rose re- growing. Page 7 of 21 Richard R. Hefley – Consulting Arborist – 360-385-2921 – rkhefley@olypen.com Above pair of photos show the multi-trunked stems of the Bitter Cherry trees growing from a point just below the crest of the slope. Mid-Slope – Bigleaf Maple grove - All trees on the northern half of the slope are Bigleaf Maples. Page 8 of 21 Richard R. Hefley – Consulting Arborist – 360-385-2921 – rkhefley@olypen.com A clump of 5 Bigleaf Maples. It appears highly likely these trees were cut several decades ago and have been allowed to re-grow as multiple-trunked trees. Note the “holes” on the lower trunks; this is the point where they were probably cut and have regrown from those points (these may have been cut multiple times) Another Bigleaf Maple with the same tell-tale wounds. Page 9 of 21 Richard R. Hefley – Consulting Arborist – 360-385-2921 – rkhefley@olypen.com A good example of a Bigleaf maple on the slope that was cut back and then regrown into multiple tops. Because tree trunks increase in diameter with each passing year, these multiple-trunked trees will eventually grow together and force each other to split apart. This is a structural flaw. On top of the slope where the house and view corridor will be present, these multi-trunked trees appear as an impenetrable thicket. Page 10 of 21 Richard R. Hefley – Consulting Arborist – 360-385-2921 – rkhefley@olypen.com This Bigleaf Maple is located farther down North Maple Street. This is a good example of how a mature Maple appears that has not been repeatedly pruned back. They are typically large single- trunked trees. Not one of the more than a dozen trees on the slope has a single trunk. Looking upslope – A groundcover of Western Swordfern is ideal in the bare spots on this slope. Having an upper story of small evergreen trees would be an even better addition. Page 11 of 21 Richard R. Hefley – Consulting Arborist – 360-385-2921 – rkhefley@olypen.com On the Beach - Page 12 of 21 Richard R. Hefley – Consulting Arborist – 360-385-2921 – rkhefley@olypen.com Bare sections of the slope that would benefit from the addition of fibrous- rooted native evergreen groundcovers and small trees such as Sword Fern and Shore Pine, among others. Looking towards the south-west and upslope from the beach. Fortunately, there is little evidence of tidal or wave erosion in this sheltered side of the bay. Much of the slope has little vegetation, probably due to the deep shade cast by the Bigleaf Maples that dominate this area during the summer. Page 13 of 21 Richard R. Hefley – Consulting Arborist – 360-385-2921 – rkhefley@olypen.com Discussion – The slope running from 142 North Maple Street down to the beach is traversable, sandy, shows some evidence of groundwater erosion in places but there are no signs of slides or soil-creeping as evidenced by the lack of jack-strawed trees. The vegetation is dominated by Bigleaf Maples that appear to have been cut back to within 2-3’ of ground level at least once. The result of this pruning has been a dense canopy of structurally flawed canopies that will begin to split apart in future years. Another consequence of this dense deciduous broadleaf tree canopy has been to prevent other vegetation from succeeding on this slope, particularly The lack of “jack- strawed” trees, trees growing with a pronounced curve in the trunk, indicate this is a relatively stable slope. However, being sandy, it is subject to surface erosion due to the lack of evergreen groundcovers. Looking upslope from the north-east corner – In the foreground is a noxious weed, Himalayan Blackberry, which should be mitigated (hopefully eradicated!) if possible. Page 14 of 21 Richard R. Hefley – Consulting Arborist – 360-385-2921 – rkhefley@olypen.com evergreen vegetation that would be far more beneficial to its long-term stability and erosion mitigating properties. Part of the problem with deciduous trees and erosion control is that there is no foliage present to interdict the hard rains that fall in our rainy season of November to March. Raindrops striking bare ground are a major cause of shallow soil disruption leading to erosion. The lack of evergreen vegetation also promotes the sheeting of groundwater from surfaces above the crest of the slope. The amount of stormwater is likely to increase as properties uphill are developed and there is more impenetrable ground (driveways, roofs) to shunt away the rain. Another issue is the root systems of Bigleaf Maples are not as dense or fibrous as many of our evergreen conifers, particularly Western Red Cedar or Pacific Yew. There is one redeeming trait of Bigleaf Maples that lends itself to the balance of slope stability and a view corridor; these trees are almost indestructible. Evidence is readily abundant to the casual observer, no matter how hard these trees are pruned back, they will respond with vigor. As such, it is possible to cut them back as hard as they have been cut back on previous occasions with little or no added risk to the stability and erosion likelihood of the slope. I believe this ecosystem, from the building site to the bay, would benefit from an increase in the amount and variety of evergreen vegetation. The first step towards introducing more appropriate native vegetation is to control the height and spread of the Bigleaf Maples, as well as the few Bitter Cherries. This will allow critical light resources to reach the ground as well as reduce some of the competition for water and nutrients with the (overbearing) maples. As evergreen vegetation is established it will greatly mitigate water runoff and evapotranspiration during the wet winter months when it is most critically needed. There is one maxim of arboriculture that seems to recur through every aspect of the discipline, and that is the Rule of 25%. For example, when pruning any tree or shrub, removals should be limited to 25%. When cutting back a limb to a strong lateral, the lateral should be at least 25% the size of the portion being removed, and so on. As such, while working on this slope, I recommend doing so in increments of 25% of the area at one time. In practice, I would cut back 25% of the Bigleaf Maples and Bitter Cherries to stumps (they will resprout, I promise), and then replant the area once covered by those deciduous canopies with native evergreen groundcovers and small-growing trees. The “25% Rule” is not etched in stone, and one could likely argue it is little more than superstition and more depends on the species, health, age of plant, seasons etc., but it is still an effective guiding principle. There will be instances where it may need to be exceeded, and that is perfectly fine. I leave much discretion to the arborist working in the tree at hand. Recommendations – The first step is to add low native evergreens, specifically Sword Fern, but others such as Low Oregon Grape and Salal would increase the biodiversity, to the buffer zone that runs from the crest of the slope back westwards towards the proposed development. This is the first interdiction and filtering of seasonal stormwater that flows down into the bay. This area currently contains many young Nootka Roses that are regrowing after they have been mown for many years. These should be allowed to remain and grow up through the Ferns and other evergreens. I recommend that paths be planned for and maintained through this buffer zone to make future maintenance easier and more effective. Page 15 of 21 Richard R. Hefley – Consulting Arborist – 360-385-2921 – rkhefley@olypen.com New plants should be seedlings or in 4” pots to minimize soil disturbance where possible. Tree seedlings are more effectively grown using the protection of a “tree tube”. These tubes prevent grazing critters from damaging the seedlings, as well as providing a more humid atmosphere to keep their leaves/needles moist, and funnels rainwater directly to their roots. The best time for planting is late October/November, before the winter rains that saturate the ground have begun in earnest. There is ample water to keep the plants alive and the soil is still warm, promoting root growth which will help the seedlings survive their first real test, the following summer drought. I recommend that 25% of the Bigleaf Maples be cut back to their trunks as they have been successfully done before. If there are approximately 16 trees, choose 4 to cut back to the trunk. To mitigate possible fire danger, most of the multiple trunks should be removed from the slope, but some may be retained and placed horizontally, across the face of the slope, preferably anchored on the downslope side by the remaining Maple stump or pruned tree. These anchor-logs help to slow water and eroded soil as well as provide small terraces for the planting of the new evergreen vegetation. Washington State Dept of Ecology does recommend fallen trees to remain in the water where they provide critical habitat and food for our maritime ecosystem, so some of the pruned trunks may remain on the beach and be beneficial. However, if there are more than can be adequately placed in/near water or anchored on the slope, these will need to be removed and chipped (add the woodchips back to the slope and buffer area to serve as mulch) or hauled away. The remaining 3/4s of the trees (approx. 12 trees…though I was not positive of property lines while clambering on the slope) may also have their canopies reduced by 25%, either by removing entire multiple leaders, or pruning back all leaders by 25% to suitably-sized lateral limbs. This, I believe, is a very conservative approach to mitigating the several challenges faced here. The process of the 25% pruning may be repeated in subsequent years as is practical. Pruning should be done during dry periods to limit possible damage to the slope. Following the pruning should come the planting in the areas formerly covered by the canopies of the heavily pruned trees, those cut back to the stumps. Groundcovers (Ferns, Salal, Mahonia) should be planted on 18”-24” centers (spaced apart) and small trees (Shore Pine, Pacific Yew) spaced 8-12’ apart. I recommend the Shore Pine and Sword Ferns as the primary replacement species because of their toleration of drought, disease, deer (a growing epidemic in this area), and plant size. Between the techniques of the “hard pruning”, (back to the stumps) and “crown reduction/thinning,” the view corridor should be restored and maintained. The replanting of the slope and buffer zone in native evergreen groundcovers and trees should greatly improve stormwater quantity (and quality) and mitigate erosion, as well as increase the biodiversity of these ecosystems. *The addition of a Rain Garden between the buffer zone and the development will add a farther layer of water mitigation. Noxious Weeds – At the time of my visit the only noxious weed I observed was Himalayan Blackberry. There were a few canes present near the crest of the slope, and a large clump at the toe of the slope (though I am unsure whose property they were on). These plants should be eradicated when and wherever encountered. Barring digging out the clumps (digging is frowned on regarding slopes and shorelines), Page 16 of 21 Richard R. Hefley – Consulting Arborist – 360-385-2921 – rkhefley@olypen.com the best method I have encountered is to cut the cane and paint of an herbicide “concentrate” (not diluted/ not ready-to-use) during the warm summer months. The Jefferson County Noxious Weed Board may have more and better suggestions. WAIVER OF LIABILITY: Many factors affect a tree’s health and stability that are not discernible in the course of a visual examination. My conclusions represent an opinion of a tree’s health and stability at this particular point in time. This report does not guarantee the future safety of the trees or predict future events that may affect these trees. A second opinion by a qualified assessor is always recommended. The property owner is responsible for scheduling future examinations and/or recommended maintenance. The property owner is responsible for obtaining required permits from all concerned governing bodies from federal to state, county, city, and home owner associations. The property owner is responsible for obtaining and providing all applicable codes, covenants and restrictions (CC&Rs) that apply. The client shall hold the evaluator harmless for injuries or damages incurred if recommendations are not heeded or for acts of nature beyond reasonable expectations such as severe winds, excessive rain, heavy snow loads, ice, earthquakes etc. This report and all attachments, enclosures and references are confidential and intended for the use of the client referenced above. They may not be reproduced, used in any way or disseminated in any form without the consent of the client and Richard Hefley – Consulting Arborist. Page 17 of 21 Richard R. Hefley – Consulting Arborist – 360-385-2921 – rkhefley@olypen.com Richard R. Hefley Consulting Arborist 360-385-2921 rkhefley@olypen.com PO Box 177 101 Renier Road Nordland WA 98358 APPENDICES Tree Pruning Guide Click to view this downloadable PowerPoint presentation for information on tree pruning. Pruning • Limit at planting time to removing broken, crossing, rubbing branches, alleviating structure problem • Remove basal sprouts • Encourage a central leader • Leave lower branches on the tree to stimulate root and trunk diameter growth Page 18 of 21 Richard R. Hefley – Consulting Arborist – 360-385-2921 – rkhefley@olypen.com Common Pruning Mistakes • Do not thin the tree to compensate for root loss • Do not raise lower limbs, these will help add girth to trunk and root growth • Pruning paints and sealers do not prevent decay or promote rapid closure, not recommended • Pruning Flush cutting branch back to trunk is incorrect, it wounds the trunk and causes decay. • Make the cut along branch collar. Page 19 of 21 Richard R. Hefley – Consulting Arborist – 360-385-2921 – rkhefley@olypen.com Notes on Pruning: Pruning should be done in conformation to ANSI A300 Standards. When pruning trees, I recommend the woody debris be ground into chips or broken down into the smallest pieces possible and distributed throughout the area beneath the tree canopy. This debris will break down and provide future nutrients for the remaining trees, as well as build up the soil layers and aid the mycchorizal organisms that live in the soil and are a critical part of water and nutrient uptake (yes, the soil is, literally, alive). Light pruning (10% or less of the live canopy) can be done any time of year. Heavy pruning is best left for winter months when trees are in their maximum state of dormancy. Pruning should never exceed 25% of a tree’s canopy, though this amount can be modified depending on the tree’s age, health and species. If pruning for safety reasons then the season should be discounted and pruning take place as soon as practical. It is best to have all safety pruning completed before the end of October, which generally is the commencement of our wind-storm season. Another viable option is to leave the branch stubs in place to serve as habitat for beneficial organisms, from fungi to mammals. This technique (or lack thereof) is being more and more encouraged by tree care professionals as it replicated what would be done naturally. In a similar vein, wood chips and debris are encouraged to be allowed to remain beneath the tree to decompose and serve as a source of mulch and nutrients for the tree. Pruning For View There are essentially five methods for pruning trees for view; 1. Crown Cleaning / Thinning 2. Windowing 3. Crown Raising Page 20 of 21 Richard R. Hefley – Consulting Arborist – 360-385-2921 – rkhefley@olypen.com 4. Crown Reduction It is important to not remove too much foliage. The “rule of thumb” is to remove no more than 25% of the canopy at one time, but this should be adjusted to account for the species, the age, the health, and the time of year the pruning is done. Many say this amount may be removed yearly, but my opinion is that one should wait several years before conducting another “maximum” pruning (25%) to avoid stress on the tree and allow more foliage to take the place of what was lost. Light pruning (less than 10% of canopy) can be done yearly and regardless of the season. 5. Living Habitat Tree. Another technique is a more severe alteration of the tree, the creation of a Habitat Tree, which entails removing as much as 80% of the tree (and most likely shortening the life span of the tree). This technique is replicating natural storm damage trees suffer which results in their losing the majority of their crowns while retaining enough foliage to survive and provide habitat for a large variety of birds, animals and fungi. The tree will also retain its critical functions of transpiration, rainfall interdiction and soil cohesion. There are no studies to my knowledge on the number of Living Habitat Trees suitable for any given area, but I would err on the cautious side and estimate that no more than 10% of trees in an area should be converted into Habitat Trees, and probably fewer The tallest tree in the photo is a Douglas Fir that was topped naturally in a storm. It is now riddled with woodpecker holes and is habitat for far more organisms than it was as a healthy actively growing tree. Page 21 of 21 Richard R. Hefley – Consulting Arborist – 360-385-2921 – rkhefley@olypen.com For information on Rain Gardens - https://extension.wsu.edu/raingarden/featured-rain-gardens/ For information of Noxious Weeds in Jefferson County - https://www.co.jefferson.wa.us/195/Noxious- Weed-Control-Board Tree Protection Tubes for seedlings on slope - https://www.forestry- suppliers.com/product_pages/products.php?mi=16231&itemnum=17026&redir=Y