The shape of a tree is very important in determining its timber volume recovery and value. A Technical Note just published by the Forestry Commission provides guidance on the methods that can be used to assess stem straightness in standing trees.
The Note looks at three methods: visual assessment, photogrammetric measurement and terrestrial lidar. It provides basic guidance on each of the techniques and recommendations for their use.
Effective assessment of stem straightness both at individual tree and stand level, prior to harvesting enables managers and researchers to:
- identify better quality stands, or the better trees within stands;
- optimise resource use by identifying and marketing material according to specific processor requirements;
- reduce the incidence of rejected logs or loads;
- obtain the best prices for logs;
- include log quality information in forest inventory, production forecasting and forest planning;
- inform processors about the quality of future supplies.
Author Andrew Price of Forest Research, said: “The ability to make an effective assessment before harvesting is useful for forest managers and practitioners to improve forecasting, planning, marketing and resource use.
“Each method has its own advantages and disadvantages depending on the requirements of the forest manager. For example, if a low cost and high speed method is required the estimates provided by visual assessment may currently be the best option. The photogrammetric technique is highly accurate but technically demanding and time-consuming. Terrestrial lidar can be used for plot-based measurements and is rapidly becoming more automated, which will speed up the method and make it more attractive to users.”
It is an unpriced publication available to download from the on-line publications catalogue at http://www.forestry.gov.uk/publications/whatsnew