Agenda - Parks and Recreation Commission - 10/14/1993

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10 Treatment o f Damaged Plants · 'When a tree is injured by con- struction activities, energy and resources normally used for growth must be redirected towards the process of wound closure and regrowth. During tt'ds critical period plants are particularly vulnerable to additional stress, especially insects, diseases, and severe weather. You can minimize these problems by quickly treating the damage, WA TER Construction activities often alter --the amounts of water received by ' trees. Thoroughly water plants befo're and immediately after they receive an), kind of direct damage (e.g,, severed roots). Continue periodic watering (four to five times per summer) throughout the next growing season. Be careful, not to overwater your trees. A one-inch depth of water applied throughout the PRZ is a good -. rule of thumb. A tin can or glass )ar · can be used to measure the amount of water applied if an overhead irrigation system is used. Concentrate most of · the Water on undamaged sections of . the root system. : . Two to three inches of mulch - (wood chips or bark) spre'ad over as ' much of the root system as practical ,,',,ill help the tree retain water and. stimulate root regeneration. Living · grouted c?vers over the root system will have a similar effect, and may be · more a&sthetic. Apply these tech- .'~quek to an), deciduous tree exhibit- .lng wilted leaves or any coniferous tree dropping excessive amounts of needles from the inner branches. · Drainage Systems and grade changes may cause some trees to ;receive too much water. Species differ · in the amount of water they can · tolerate .(Table 1). !ntolerant plantk Wilt exhibit twig arid brarich death, Don't wait for these, kymptoms to · appear. If you suspect ),our plant is Figure 76. Before you remove fill that ha~ been added around trees, take vertical somplei to determine t~ow deep you need toga. receiving too much water, contact a tree-care specialist for an evaluation of the problen't. Treatment differs by tree species and by the amount of time the water remains on or close to.the surface. For some species, a retaining ,,,.'all or culvert may be needed to redirect the flow of water. EXCA VA TION OF BA CK- FILLED TREI!5 If you or your tree-care specialist has determined that excessive soil additions have been made around valuable trees, efforts should be made to restore the original grade· at least within the PRZ. Approach this grade restoration carefully. Determine how much film l~as been added by sampling depths at several different ]xfi~ds within the PRZ (Figure 16). If the depth is great (more than 12 inches), you may remove most of the backfill with mechanical equipment. Once you are within 10 to 12 inches of the original grade, complete the fill excavation carefully with shovels and rakes· Make certain no soil is piled up against t}~e tree trunk, and aerifv the soil within the Pl~ to complete the operation. If the tree is already exhibiting advanced symptoms of decline, however, restoration.to original grade will probably be fruitless..In ttxis case, remove the tree and plant a new one. A ERA TION ' Soil compaction around a tree's roots may cause leaf wilt, early fall coloring, top dieback, and slow growth. Reduce compaction by carefulh, drilling a series of twodnch diameter holes in the soil to a depth of twelve to eighteen inches. Begin three feet from the tree trunk and continue drilling at two-foot intervals in concentric rings around the tree out to the P~ (Figure 17). Each hole may be refilled with sand, peat moss, or Figure ?7. A series of two-inch holes 12 to 18 inches deep will help alleviate root damage caused b), compact ion.