312 Vogt et al.: The Costs of Maintaining and Not Maintaining the Urban Forest bens (1978) outlined four direct costs of maple decline: “1) periodic deadwood removal, 2) even- tual removal cost, 3) replanting or replacement cost, and 4) loss in value of the mature tree” (p. 33). Rubens (1978) declared that, “The cost of soil desalination on a continuous basis to protect healthy sugar maples (Acer saccharum) not af- fected by other environmental or man-made stresses is less than the costs attributable to non- provision of this maintenance” (p. 41), although specific costs were not determined empirically. Other authors have noted additional methods of mitigating maple decline without providing dollar figures, including application of manga- nese compounds directly to the trunk or foliage (Smith and Mitchell 1977), and soil injection or dry application of manganese sulfate monohy- drate (Funk and Peterson 1980); applications of nitrogen were ineffective (Rich and Walton 1979). Fixing chlorosis Himelick and Himelick (1980) analyzed meth- ods of ameliorating chlorosis in several species via iron treatments, noting that excessive application of calcium or phosphorous in turf fertilizers or too much soil moisture could contribute to chlorosis. These authors observed that injecting the tree with ferric citrate or ferric ammonium citrate is a “rea- sonably effective and economical” method of treat- ing chlorosis in pin oak (Quercus palustris) and sweetgum trees (Liquidambar styraciflua) (Hime- lick and Himelick 1980), although again no costs figures were provided. Smith (1988) also discussed methods for ameliorating nutrient-deficiency- related leaf chlorosis, but did not link chlorosis to tree performance, benefits, or other maintenance needs outside of the chlorosis treatment itself. Costs of not managing soils or nutrients None of the aforementioned studies provided empirical estimates of the costs of nutrient treat- ments. Additionally, few studies have quantified the impacts of nutrient treatments on tree struc- ture (e.g., survival or growth), function, or benefits. Studies that did provide estimates of the im- pact of treatments on tree survival (Gilman 2004; Rich and Walton 1979) and growth (Harris et al. 2008) found no effect of fertilization, or a small impact on root growth (Percival et al. 2004). ©2015 International Society of Arboriculture Tree support systems Several tree support systems, including staking, ca- bling, bracing, and propping serve the purpose of supporting a tree and improving strength during periods of vulnerability. Staking serves to support small or recently planted trees or trees in windy areas (Smiley and Lily 2006). Bracing, cabling, and propping serve as methods of supporting weakened, old, or severely damaged trees that would otherwise fail, thereby prolonging their useful life. Relatively few studies have discussed the economic benefits of staking trees. Black (1978) discussed staking young trees as a means of reducing vandalism. Bracing and cabling as methods of supporting mature trees were discussed by Mayne (1975) and others, but the cur- rent literature review yielded no articles on the eco- nomics—benefits or costs—of cabling and bracing. Protection during construction Protecting trees during construction is a means of preserving many of the benefits provided by trees that otherwise might be damaged or removed during construction of a building or road. Protection ac- tivities theoretically have costs. Koeser et al. (2013) found that trees near road construction activities were twice as likely to succumb to mortality as trees not adjacent to road construction. Tree protection during building construction can include estab- lishing a barrier between the tree and construc- tion activities, creating “disturbance-free zones” around wooded areas to limit root disturbance, and grading construction areas to guide potentially contaminated construction runoff away from root zones (Anderson and Barrows-Broaddus 1989). Tree protection during road construction or utility installation can include tunneling and boring with an aim to avoid root damage (Yingling et al. 1979; Jim 2003). Tree protection and preser- vation during construction is a specialized field composed of consulting arborists and contractors who rarely publish, and thus few studies explicitly examining the economics of tree protection exist. Economics of tree protection The loss of forest benefits due to inadequate pro- tection of existing trees or forests from damage during construction or other activities results in a number of types of costs: costs to the final homeowner, who might otherwise benefit from
November 2015
| Title Name |
Pages |
Delete |
Url |
| Empty |
Search Text Block
Page #page_num
#doc_title
Hi $receivername|$receiveremail,
$sendername|$senderemail wrote these comments for you:
$message
$sendername|$senderemail would like for you to view the following digital edition.
Please click on the page below to be directed to the digital edition:
$thumbnail$pagenum
$link$pagenum
Your form submission was a success. You will be contacted by Washington Gas with follow-up information regarding your request.
This process might take longer please wait
