知识与财富的链接
【目的】研究不同干燥温度条件下红锥树盘干燥过程中心材、边材材色变化及干燥缺陷,为红锥木材干燥工艺和高价值利用提供科学依据。【方法】在广西凭祥市中国林业科学研究院热带林业实验中心39年生红锥人工林内设置5块20m×30m的样地,每块样地选取1株优势木进行解析,截取主干0～2m段树盘分别在60,80和120℃的恒温干燥箱内进行干燥处理,以室内常温条件下干燥为对照,每隔2h测定不同处理树盘材色(心材材色变化指数ΔLht~*、Δaht~*、Δbht~*和ΔEht~*,边材材色变化指数ΔLst~*Δast~*、Δbst~*和ΔEst~*)和心材、边材的裂纹数目、裂纹长度、裂纹宽度,采用三次曲线拟合干燥时间与材色变化的回归模型,应用单因素方差分析探究干燥温度对心材、边材的裂纹数目、裂纹长度和裂纹宽度等干燥缺陷的影响。【结果】3个干燥温度处理下,心材材色特征参数ΔLht~*、Δaht...
【Objective】Color changes and drying defects of heartwood and sapwood areas of stem discs on Castanopsis hystrix different drying treatments were assessed to provide scientific evidences for kiln drying and utilization of C. hystrix.【Methods】Five 20 m×30 m plots were set in a 39-year-old pure C. hystrix plantation at the Experimental Centre of Tropical Forestry of Chinese Academy of Forestry in Pingxiang,Guangxi.One dominant tree in each plot was sampled for stem analysis based on growth performance.Four discs from each dominant tree at the height of 0-2 m were collected.One disc from each sample tree was dried at room temperature as control and the other three were dried in electrically heated drying cabinet under 60,80 and 120 ℃,respectively.Wood color parameters (ΔL*ht,Δa*ht,Δb*ht and ΔE*ht for heartwood and ΔL*st,Δa*st,Δb*st and ΔE*st for sapwood) and drying defects (number and size of cracks of discs) were measured and recorded every 2 hours.Cubic curve was applied to explore the relationship between drying time and color change,and one-way analysis of variance was adopted to study the effects of drying treatments on above drying defects.【Result】The heartwood color parameters of ΔL*ht,Δa*ht,Δb*ht and ΔE*ht were －10.59―2.85,-2.06－1.89,－4.33－-0.34 and 3.11－10.80 under drying temperature treatments.The corresponding values of ΔL*st,Δa*st,Δb*st and ΔE*st of sapwood were -6.99－17.32,-0.55－4.01,0.94－8.46 and 1.83－19.36,respectively.The highest variation was observed in brightness both for sapwood and heartwood,followed by total color change.The color parameter redness and yellowness showed the lowest variations.The number and length of cracks for heartwood and sapwood showed an increasing trend with the increase of drying temperature.Under 60,80 and 120 ℃ drying temperatures,the numbers of cracks in heartwood were 3.0,3.6 and 4.6 with length of 24.50,27.80 and 39.02 cm and widths of 2.85,2.36 and 4.00 mm,respectively.The number of cracks in sapwood were 0.4,0.8 and 1.0,and the lengths were 5.90,8.80 and 10.63 cm,and the widths were 1.26,4.09 and 4.47 mm,respectively.【Conclusion】Drying with 60 and 80 ℃ is recommended for high value timber drying as it could effectively reduce the color change,number and length of cracks in both the heartwood and sapwood of C. hystrix.