Human footprints in urban forests: implication of nitrogen deposition for nitrogen and carbon storage

No Thumbnail Available
File version
Author(s)
Bai, Shahla Hosseini
Xu, Zhihong
Blumfield, Timothy J
Reverchon, Frederique
Primary Supervisor
Other Supervisors
Editor(s)
Date
2015
Size
File type(s)
Location
License
Abstract

Purpose: Rising levels of nitrogen (N) deposition are influencing urban forest carbon (C) and N dynamics due to greater human disturbance compared to those in rural areas. N deposition in combination with increased atmospheric carbon dioxide (CO2) and water limitation may alter C and N storage in urban forests. This review aimed to provide a better understanding of N and C storage under N deposition scenarios in urban forests. Results: and discussion Globally, fuel combustion and biomass burning contribute in approximately 70 and 16 % of the NOx emission respectively. It is also estimated that NHy and NOx are two to four times higher in urban forests compared to rural areas. However, higher N deposition may not always result in increased N and C storage in urban forests. In fact, urban forests may even show early symptoms of N and C losses under climate change. For example, urban forests in fire-prone areas require higher frequency of burning to reduce the threat of wildfires, leading to an acceleration of C and N loss. Additionally, chronic N deposition may result in an early N loss in urban forests due to faster N saturation and soil acidification in urban forests compared to rural forests. Studies of N deposition on urban forests using N isotope composition (d15N) also showed that N loss from urban forests can occur through the direct leaching of the deposited NO3 --N. We also noted that using different 15N signal of soil and plant in combination of tree ring d15N may provide a better understanding of N movement in urban forests. Conclusions: Although urban forests may become a source of C and N faster than rural forests, N-limited urban forests may benefit from N deposition to retain both N and C stocks longer than non-N-limited urban forests. Appropriate management practices may also help to delay such symptoms; however, the main source of emission still needs to be managed to reduce both N deposition and rising atmospheric CO2 in urban forests. Otherwise, the N and C stocks in urban forests may further decline when prolonged drought conditions under global climate change increase the frequency of fires and reduce plant photosynthesis.

Journal Title

Journal of Soils and Sediments

Conference Title
Book Title
Edition
Volume

15

Issue

9

Thesis Type
Degree Program
School
Publisher link
Patent number
Funder(s)
Grant identifier(s)
Rights Statement
Rights Statement
Item Access Status
Note
Access the data
Related item(s)
Subject

Earth sciences

Environmental sciences

Environmental management

Agricultural, veterinary and food sciences

Persistent link to this record
Citation
Collections