Due to a large forested land base and difficult access, often tree lists are not available for every stand. However, aerial information is often available for every polygon of land in BC. UBC researchers have examined the potential for using aerial information to estimate tree lists where they are not available.

The application of Nearest Neighbour (closeness in auxilliary variables rather than by spatial location) methods to impute ground information from aerial data was demonstrated for two types of tree lists, a tree-by-tree list of live trees by species and diameter, and a list of wildlife trees defined as dead or recently dead and fallen trees, grouped into two size classes and two species groups, and for summary variables (e.g, basal area per ha and volume per ha).

For each type of tree list, different nearest neighbour approaches were tested by varying the distance metric used and the number of neighbours used to provide and estimate. Selecting the more than one nearest neighbour, weighting the values, and assigning these to the target polygons often yielded better results than using a single neighbour or using an unweighted average of the closest neighbours.

REPORTS, PUBLICATIONS AND PRESENTATIONS:

Possible Approaches for Relating Growth and Yield Models to Aerial Information. Part I--Literature Review and Data Sources

Possible Approaches for Relating Growth and Yield Models to Aerial Information. Part II--Example Using Existing Audit Data

[Regeneration Establishment] [Predicting Tree Lists] [Small Tree Height Growth]
[Large Tree Height Growth]  [Large Tree Diameter Increment] [Live Crown] [Mortality]