|HUYLER, A - Auburn University|
|CHAPPELKA, A - Auburn University|
|FAN, ZHAOFEI - Auburn University|
|Prior, Stephen - Steve|
Submitted to: Urban Ecosystems
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/15/2016
Publication Date: 2/1/2017
Citation: Huyler, A., Chappelka, A.H., Fan, Z., Prior, S.A. 2017. A comparison of soil carbon dynamics in residential yards with and without trees. Urban Ecosystems. 20:87-96.
Interpretive Summary: Expansion of residential areas in the southeastern US raises question on the impact on urban soil carbon (C) pools. The study was done in Auburn, AL to examine the relationship of soil C to the presence of trees. This case study revealed that aboveground tree biomass often does not correspond to increases in mean soil C across decades of home age. At 0-15 cm depth, soil C had strong positive relationships with home age but weak or no relationships with tree biomass. Mean soil C at 0-15 cm depth also increased across home age groups and aboveground tree biomass categories. Turfgrass may have a more dominant influence than trees on soil C. Perhaps a loss of vegetation C input to soil from home/yard construction, different decomposition rates across depths, and access to newly established tree roots may influence soil C changes over time.
Technical Abstract: Residential yards can provide chronosequences to discern the influence of home age and tree biomass on soil carbon (C) levels. To accomplish this goal, two separate analyses were conducted. 1) The relationship of soil C to home age was compared between 23 lawns without trees (‘pure lawns’, PL) and 44 lawns with trees (LwT) across the initial 50 yrs home age and at 3 depths: 0-15 cm, 15-30 cm, 30-50 cm. Within LwT, the relationship between soil C and three aboveground tree biomass (ATB) datasets were analyzed: biomass, biomass of trees = 10 m and biomass of trees = 5 m from the sample plot. 2) Mean soil C in 23 PL, 66 LwT (3-87 yrs), and 12 forested yards were compared across ascending categories of ATB and home age groups. Soil C had a significantly different relationship with home age (P = 0.03) in LwT (P = 0.033, slope = 0.011) than in PL (P = 0.097, slope = -0.011) at 15-30 cm. Biomass = 5 m had the highest explanatory power (0.40) for soil C at 15-30 cm. Mean soil C at all depths was significantly higher in the greatest ATB category (median 12386 kg) compared to the lowest (median 0 kg). Only mean soil C at 0-15 cm was significantly higher in the oldest home age group (median 79 yrs) compared to the youngest (median 7 yrs). Overall, the relationship between soil C and ATB was weakly associated with changes in mean soil C levels over time.