Effect of Urbanization on Tree Growth in Remnant Forest Patches

urbanization;Sugar Maple;Northern Red Oak;Shagbark Hickory;Natural Resources and Environment

McClung, TeeganGrese, Robert ;

University of Michigan

关键词: urbanization;    Sugar Maple;    Northern Red Oak;    Shagbark Hickory;    Natural Resources and Environment;   

Others  :  https://deepblue.lib.umich.edu/bitstream/handle/2027.42/136231/McClung_Teegan_Thesis.pdf?sequence=1&isAllowed=y

瑞士|英语

来源: The Illinois Digital Environment for Access to Learning and Scholarship

【 摘 要 】

Land conversion and increasing impervious surface cover are affecting forests across thelandscape by increasing local temperatures and altering ecosystem processes. In this study, weassessed the impact of impervious surface cover and other environmental, landscape, or climatefactors on the growth of trees in adjacent forest patches. Tree cores were collected from 36 Acersaccharum, 40 Carya ovata, and 45 Quercus rubra trees in 11 deciduous forests in SoutheasternMichigan and their annual radial growth measured from 1985 to 2014. Soil and stand basal areadata were collected in each forest and distance from edge, mean impervious surface percentagewithin 250 m, and percent slope were calculated for each individual from National Land CoverDatasets. Annual average temperature, total precipitation, and Palmer Drought Severity Index datawas also collected from the National Climatic Data Center.Tree growth rate was modeled by species and diameter using a Bayesian framework withnon-informative priors as a function of percent impervious surface. Running models with severalcombinations of explanatory variables (distance to edge, slope, percent sand, total nitrogen, basalarea, and climatic variables) did not improve the goodness of fit so random effects terms forindividual growth and year were added, in addition to antecedent terms, which helped account forthe potential effect of previous years’ growth.The model resulted in R2 values of 0.67 for A. saccharum, 0.71 for C. ovata, and 0.88 for Q.rubra. Higher levels of impervious surface did significantly, negatively affect the growth of smallA. saccharum individuals and growth in an individual is strongly dependent of growth from theprevious year. The year random effects term showed weak correlations with summer temperatures(-), spring and summer (+) precipitation, and the Palmer Drought Severity Index (-). Theseobservations imply that not all trees species and size classes are affected equally by urbanization.Remnant forest patches typically experience little to no management and largely need to be selfsustainingover time, which highlights the need for a better understanding of how urbanization willaffect these ecosystems.