Abstract
This study was conducted to show the effect of compression wood on some anatomical characteristics and mechanical characteristics of brutia pine Pinus brutia Ten. trees growing naturally at Dohuk provenance and to compare it with the standing trees (tree leaning type) for four levels of stem height, and between compression wood and opposite wood present in front of compression wood (wood location) and between heart wood and sap wood (wood type) to know the possibility of using tree stems containing compression wood in various technological wood products. The results showed that the highest values for tracheid length and tracheid diameter were in the standing trees, while there was little increase in tracheid cell wall thickness of leaning trees. Also leaning trees were significantly better than standing trees in rankel ratio. It was found that there was increase in the values of most anatomical characteristics from stem base to stem top. The lowest values for the studied anatomical characteristics were in the first level of height ( 1.5 m), then they began to increase gradually by increasing stem height level until they reached the maximum values at the 3rd level of height (4.5m), then these values were decreased slightly at the 4th level of the height ( 6 m). The results indicated that the highest mean values of tracheid length and diameter were in opposite wood. While there was slight increase in tracheid cell wall thickness in compression wood, but it was not significantly different to opposite wood. Also, there was significant increase in rankel ratio in compression wood compared with opposite wood. Sapwood showed the best values for all anatomical characteristics except rankel ratio compared with heart wood. This indicated that most anatomical characteristics will increase by increasing the distance from pith to bark which may relate to age effect. It was found that the highest mean of modulus of rupture (MOR) and modulus of elasticity (MOE) and tension perpendicular to grain was in the standing trees and significantly higher compared to the leaning trees. Also, it was noticed that the highest values of the mechanical characteristics were in first height (1.5m), they decreased gradually by increasing height levels and it reached lower value at the 3rd height level (4.5 m) then they increased slightly in the 4th height level (6 m). Also, the study showed that opposite wood were better than compression wood in all mechanical characteristics. Sapwood showed the highest values of the studied mechanical characteristics compared to heartwood. The results showed that the base of the leaning tree stem was eccentric, and it became more centric by increasing height level.
