Five instruments for measuring tree height: an evaluation
Five instruments were tested for reliability in measuring tree heights under realistic conditions. Four linear models were used to determine if tree height can be measured unbiasedly over all tree sizes and if any of the instruments were more efficient in estimating tree height. The laser height finder was the only instrument to produce unbiased estimates of the true hiehgt for all four linear models. an accuracy test showed the clinometer and enbeeco instruments produced biased results in 0-300 and > 66 ft height classes respectively. The results for the laser may be misleading due to the limited amount of data collected with this instrument. The results (subjectively) confirm that trees up to 40 ft are measured very accurately with no exceptions for the clinometer, relaskop, and enbeeco. The tele-relaskop generally produced results that were poorer than the other instruments.