Forestry Management

November, 1987

Providing Measurement Data on Young Stands Based on Large Scale Aerial Photography

	Large scale photography (LSP) has become an important tool in forestry applications and in particular regeneration surveys. Hunter and Associates was retained by the Ontario Ministry of Natural Resources (OMNR) to examine 160 stands across the boreal forest region in Ontario, covering a range of soil conditions, in order to characterize the species distribution patterns. The data would allow OMNR to: determine the magnitude of the potential biases inherent in OMNR's current regeneration assessment program; test the robustness of certain procedures and characteristics of type of spatial distributions; and aid in developing procedures for characterizing the species-spacing patterns as required in growth modelling. A simultaneous fixed-base camera system with two Hasselblad MK-70 photogrammetric cameras was mounted on a Bell Jetranger helicopter. The use of a helicopter platform for stocking and regeneration surveys offers the necessary flexibility for LSP plot selection where assessment blocks are randomly distributed, variable in size, and where the spatial distribution of plots is highly desireable. A Zeiss G-2 stereocord and mensuration software developed by Hunter and Associates were used to obtain basic measurement data of 6 to 12 plots per stand sampled (1,500 plots total), including species, height and x,y location. Analytical data derived from the measurements included mean distances and variances to nearest neighbours within a plot, point-tree distances to various fixe points in the plot, and area for triangles using pairs of point-trees and fixed lattice points.

© 2001, Hunter GIS