Old-Growth Forest Canopy Structure and Its Relationship to Throughfall Interception
Authors: Nalini M. Nadkarni1; Mark M. Sumera2
Source: Forest Science, Volume 50, Number 3, June 2004 , pp. 290-298(9)
Abstract:
Structural elements of the forest canopy such as foliage, branches, and epiphytes intercept, retain, and regulate inputs of matter and energy to the forest floor in spatially variable ways. Most studies of forest structure-function have analyzed relationships between canopy structure and the spatial distribution of inputs at the forest stand level. Few studies have focused on within-canopy spatial scales or identified the functional roles of particular structural components. Our objective was to quantitatively assess the amount of canopy structural material to a critical functional attribute: canopy interception of rainfall. We investigated forest canopy structure with a novel technique, vertical canopy cylinder transects, that uses access from a construction crane in an old-growth coniferous forest in Washington State. We characterized the diversity and composition of forest structural elements (tree foliage and branches by species, epiphytes by functional group) and found the majority of the foliage and epiphytes concentrated in the upper- to mid-canopy, with some vertical stratification of the epiphyte functional groups. We also quantified one aspect of forest function, the volume and variability of throughfall interception. We documented a strong relationship between the amount of structural elements and rainfall interception (R2 = 0.79). This approach of quantifying three-dimensional canopy structure at particular locations had higher predictive ability for throughfall volume than previous approaches that were not able to gain direct access to canopy components. FOR. SCI. 50(3):290298.Keywords: Canopy crane; forest ecology; hydrology; throughfall; Wind River; environmental management; forest; forest management; forest resources; forestry; forestry research; forestry science; natural resources; natural resource management
Document Type: Regular article
Affiliations: 1: Member of the Faculty The Evergreen State College Olympia WA 98505 Phone: (360) 867-6621;, Fax: (360) 866-6794, Email: nadkarnn@evergreen.edu 2: Research Associate The Evergreen State College Olympia WA 98505 Phone: (360) 867-6788
