Multi-scale Drivers of Spatial Variation in Old-Growth Forest Carbon Density Disentangled with Lidar and an Individual-Based Landscape Model
Authored by Werner Rammer, Rupert Seidl, Thomas A Spies, E Ashley Steel, Robert J Pabst, Keith Olsen
Date Published: 2012
DOI: 10.1007/s10021-012-9587-2
Sponsors:
European Union
United States Department of Agriculture (USDA)
United States National Science Foundation (NSF)
Platforms:
iLand
Model Documentation:
Other Narrative
Flow charts
Mathematical description
Model Code URLs:
Model code not found
Abstract
Forest ecosystems are the most important terrestrial carbon (C) storage
globally, and presently mitigate anthropogenic climate change by acting
as a large and persistent sink for atmospheric CO2. Yet, forest C
density varies greatly in space, both globally and at stand and
landscape levels. Understanding the multi-scale drivers of this
variation is a prerequisite for robust and effective climate change
mitigation in ecosystem management. Here, we used airborne light
detection and ranging (Lidar) and a novel high-resolution simulation
model of landscape dynamics (iLand) to identify the drivers of variation
in C density for an old-growth forest landscape in Oregon, USA. With
total ecosystem C in excess of 1 Gt ha(-1) these ecosystems are among
the most C-rich globally. Our findings revealed considerable spatial
variability in stand-level C density across the landscape.
Notwithstanding the distinct environmental gradients in our mountainous
study area only 55.3\% of this variation was explained by environmental
drivers, with radiation and soil physical properties having a stronger
influence than temperature and precipitation. The remaining variation in
C stocks was largely attributable to emerging properties of stand
dynamics (that is, stand structure and composition). Not only were
density- and size-related indicators positively associated with C stocks
but also diversity in composition and structure, documenting a close
link between biodiversity and ecosystem functioning. We conclude that
the complexity of old-growth forests contributes to their sustained high
C levels, a finding that is relevant to managing forests for climate
change mitigation.
Tags
Productivity
Diversity
Ecosystem
Climate-change
Structural complexity
Pacific-northwest
Use efficiency
Net primary production
Douglas-fir forests
Western oregon