The height and seasonal variation of foliage clumping: implications for the remote sensing retrievals
Abstract
Clumping index (CI) describes the level of foliage grouping within distinct canopy structures relative to a random distribution. Vegetation foliage clumping significantly alters its radiation environment and affects vegetation growth as well as water and carbon cycles. In moderate to dense forest stands, in-situ measurements near the ground surface may considerably underestimate the overall canopy-level clumping effect. This is because the large gaps between tree crowns at upper levels of the canopy may not be all measured near the ground due to obscurity by lower vegetation of branches. To assess the possible role of the vertical distribution of foliage clumping and the differences from the CI values measured at the forest floor, measurements of CI at different heights were conducted at three different stands: native cloud rainforest stand in Hawai'i, mature birch dominated stand in Jarvselja, Estonia, and boreal evergreen needleleaf stand in Hyytiala, Finland. Additionally, the seasonal variation of foliage clumping at scales larger than the shoot is reported for two RAMI birch and pine sites in Jarvselja, Estonia. This information about height and seasonal variations of CI is shown to be important for correct estimating and validating the foliage clumping from airborne/satellite remote sensing.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2011
- Bibcode:
- 2011AGUFM.B13A0525P
- Keywords:
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- 0400 BIOGEOSCIENCES;
- 0439 BIOGEOSCIENCES / Ecosystems;
- structure and dynamics;
- 0476 BIOGEOSCIENCES / Plant ecology;
- 0480 BIOGEOSCIENCES / Remote sensing