【作者】 陈少雄；

【导师】 李志辉； 黄文丁；

【作者基本信息】 中南林业科技大学 ， 森林培育， 2010， 博士

【摘要】 本研究从理论和技术两层面上对桉树中大径材培育进行了系统的分析和研究。完善了我国桉树培育理论与技术,填补了相关领域内的技术空白；为改善桉树材种结构、加速中大径材生产,降低我国木材对于国外市场的依赖,增加木材安全提供了科学依据。理论上,从中大材径培育的目标为切入点,对影响桉树中大径材培育的社会因素、自然因素、经营技术要素进行分析,建立了桉树中大径材的培育技术体系的因子结构机理模型。同时,根据所建立的中大径材培育体系中的结构因子,计算系统内主要关键因子对中大径材培育贡献率。研究结果表明：(1)经济目标、社会目标处于大径材培育技术体系解析结构模型的最顶层——目标层；社会需求、气候因子、立地因子三个因子为解析模型的第一层(最底层)；解析模型的第二层为树种选择和密度调控技术；第三层为施肥控制技术、修枝控制技术。(2)桉树中大径材培育过程中,密度控制对于胸径的贡献率最大,立地控制对树高的贡献率最大,立地控制、树种控制、肥料控制、密度控制对材积的贡献率无明显差异。对于中大径材培育,密度调控技术最为重要。(3)气候气象因子中,年降雨量最为重要,它对胸径和树高的生长影响都达到极显著水平,但对胸径生长是负面而对树高是正面影响。通过对广东省樟木头林场多种桉树选择试验及尾巨桉间伐试验研究间伐效应,对16年生尾巨桉6种造林初植密度试验,研究结果表明：(1)在常规造林密度情况下,中大径材培育的最低立地指数为26,培育周期16年。(2)当林分平均胸径达到18.4cm以上时,可达到中大径材培育的目标。(3)林木的胸径、树高、材积、枝下高和干形显著影响桉树木材数量和质量,因此是树种选择技术中主要表型指标。(4)本研究中的7种参试桉树综合态势差异显著。优良排序为：尾叶桉无性系>巨尾桉>大花序桉>托里桉>巨桉>柳树>粗皮桉。(5)间伐缩小了直径分布,一年后可由原来的4～7个减少到3～4；间伐显著促进了胸径的生长。(6)不同的初植密度达到中大径材培育目标的时间不同：立地指数26时,株行距为3m×5m的为84个月,3mx4m的为108个月,4m×2m的为192个月。(7)初植密度对蓄积生长的影响从27-75月生一直处于极显著状态,88月生时影响显著；99月以后不再显著；高密度林分具有早期蓄积量快速生长的特点,但到后期生长就不同了,从144个月生开始,密度3m×4m的蓄积量最大；初植密度越小,立地指数越大,中大径材出材率越高,出材量也越大。(8)本试验中有3种初植密度能够达到中大径材培育目标,在立地指数26条件下,株行距为3mx5m的在192月生时出现最高的中大径材出材率,为75.51%,2m×4m的在192月时刚刚达到中大径材培育目标,为41.44%,出材量128.16 m3.hm-2,m4(3m×4m)在LD28条件下192月生有最高的中大径材出材量,为291.43m3.hm-2。通过对尾巨桉进行施肥试验,研究结果表明：(1)6个施肥处理对平均胸径、平均高、断面积、蓄积量生长的影响都显著,但施肥的影响效果随着年龄的增大而减少。(2)3mx5m的密度施肥量为525g·株-1的平均胸径生长有一定的优势,并且在86个月生(7.2年)率先到达中大径材培育目标,3mx4m的密度施肥量为540g·株-1的平均胸径生长表现较好,并且在107个月生第二个到达中大径材培育目标。(3)磷肥对平均胸径生长的促进明显高于钾肥；磷肥对平均高生长在50月前有少量优势,而K1在62月以后则有较为明显的优势,这种优势一直保留到192月生；磷肥对蓄积生长的促进明显高于钾肥。(4)土壤养分现状与施肥研究结果表明,到192月生时,土壤中养分N、P、K含量与不同施肥处理之间几乎没有关系；施P越多,土壤中P的含量也越多,但没有达到显著水平；土壤K的关系介乎N、P之间。(5)在192月生时的速效N、P、K、Mg、Zn含量与平均胸径只在27月生时,达到显著水平；在27-144月与速效N、P、Zn含量和在27-88月生的阶段中与速效K、Mg的平均高达到显著水平；在88月生时对B敏感,平均高达到显著水平；优势高在27-192月生的全过程与速效N、P、Zn含量达到极显著水平；在27-50月生的阶段中与速效K、Mg、B达到显著水平。通过对3年生托里桉的修枝试验,研究结果表明：(1)修枝3个月后的伤口宽度有缩小的趋势,7个月时各个等级的伤口大幅度地缩小,9.5个月后,各个等级开始有完全愈合的伤口出现,特别是大伤口的愈合速度最快,12个月后,有大面积伤口已经完全愈合,伤口愈合完成率最高的属小伤口和大伤口,1年后最高达84.71%。(2)12个月后愈合速率和完成率,中等伤口属7cm和6cm,较大伤口属7cm和5cm,大伤口属8cm和6cm。(3)涂漆的伤口比涂蜡更促进伤口愈合。(4)伤口位置越高,伤口愈合越快。愈合完成率中等伤口愈合最快的树干段是2.5-4.0m；较大伤口和大伤口愈合最快的树干段是2.5-5.35m。(5)影响单板质量综合等级最大的因素是死节,其相关系数达到0.626；修枝是减少树干节疤的重要途径。通过研究施肥对主要材性指标的影响,结果表明：施肥处理1(N300 P200 K200)和2(N200P100K150)是常规用肥处理5(N100P50 K50)肥量的2倍和3倍多,在198月生时,其木材的抗弯强度、径面硬度和边材的基本密度都被显著地降低了,而其它材性指标如端面和弦面硬度、弹性模量、皱缩率、干缩率、中和心材的基本密度都没有显著变化。更多还原

【Abstract】 This research based on the silvicultural theory and regimes of eucalypt plantation for sawn log production has filled up the gaps with some technology innovation and it makes possible for improving wood product structure, speed upping the production of sawn logs, reducing the import and increasing wood security for the country.In silvicultural theory, on the target of sawn log production it was analyzed on factors of sociality, nature and management, and the structural models of factors was established. Meanwhile the contribution rates of all factors were calculated depending on the structural models and the application of error square theory. The results showed that (1) The two targets of economics and sociality were on the top layer of the models; the factors of social requirement, climate and land sites were on the bottom layer; the second layer were the factors of tree species selection and spacing; the third layer were fertiliser application and pruning.(2) In the silvicultural process of eucalypt sawn log, the contribution rates of all factors were calculated following as:density control has the largest contribution rates on DBH, site control has the largest contribution rates on H, site control, species, fertiliser, spacing have not significant difference on volume; it shows that spacing is the most factor for sawn log production. (3) Rainfall was the most important factor among the climatic factors, it significantly affect the growth of DBH and H, but the effect was negative on DBH and positive on H.In silvicutural regime research, based on the 7-year tree species trial and thining trial at Guangdong Zhangmutou Forest Farm, the tree species priority had been ranked and thining effect researched, based on the trials of 16-year spacing at Guangxi Dongmen Forest Farm, the results showed that:(1) The minimum site index for eucalypt sawn log production at normal spacing is 26, it needs 16 years. (2) It reaches the target of sawn log production when the mean DBH is 18.4 cm. (3)The timber amount and quality was significantly affected by DBH, H, volume, first branch stem and trunk form, which were the suitable factors for tree species selection.(4)The 7 tree species priority ranked as E. urophylla clone>E.urograndis>E. cloeziana> Corymbia Torelliana>E. grandis>E. saligna>E. pellita. (5)DBH distribution narrowed from 4-7 to 3-4 one year after thining, DBH growth was significantly improved by thining, it increased 12.46% and 41.87% by thining 40%,37.5% and 52.33% by thining 60% at the first and second year after thining.(6)The time to meet the target of eucalypt sawn log is different:when initial spacing is 3m×5m,84 months for site index 26,24 and 22;when initial spacing is 3m×4m,108 months for site index 26;when initial spacing is 2m×4m, only site index 26 was available to meet the target and the time was 192 months.(7)Volume was significantly affected by initial spacing from 27-88 months, it was no significant from 99 months; High-density stand have the characteristics of early rapid growth on volume, but it is different to the late, starting from 144 months old, the volume is highest of 3m×4m; the smaller the initial spacing, site index higher, the volume ratio of sawn log is much higher, the amount of material is greater.(8)Only 3 initial spacing treatments reached the sawn log target, m5 (3m×5m) had the highest wood recovery, it was 75.51% at age of 192 months when site index is 26; m4 (3mx4m) had the highest wood amount, it was 291.43m3.hm"2 at age of 192 months when site index is 28; m3 (2m×4m) just reached the target for sawn log production, it was 41.44% at age of 192 months when site index is 26.In silvicutural regime research, based on the trials of fertiliser with 6 treatments each at Guangxi Dongmen Forest Farm, The results showed that:(1)Mean DBH, H, basal area, volume growth were significantly affected by 6 fertiliser treatments, but effect decreased by time. (2)Spacing m5 (3m×5m) with fertiliser 525 g/tree was good for the growth of DBH, it reaches the sawn log target at the age of 86 months; Spacing m4 (3m×4m) with fertiliser 540 g/tree was good for the growth of DBH, it reaches the sawn log target at the age of 107 months. (3)mean DBH. P was better then K for improving DBH growth, P was slightly better than K for improving H growth before 50 months, but K1 was better from 62 months and keep the superiority till last measurement of 192 months, P was better then K for improving volume growth from the beginning to the end. (4)Soil nutrient status and fertilization results show that: there were no relationship between the content of soil nutrient N,P,K and 6 fertiliser treatments; the more P applied and the higher content of soil P level, but it did not reach the significant level, soil K is between N and P.(5)The relationship between current soil nutrition status and plantation growth, the contents of N、P、K、Mg、Zn has significantly relationship with DBH growth at the age of 27 months; The contents of N、P、Zn has significantly relationship with H growth at the period of 27-144 months and K、Mg has significantly relationship with H growth at the period of 27-88 months; B has significantly relationship with H growth at the age of 88 months. N、P、Zn has significantly relationship with dominant H growth at the period of 27-192 months; K、Mg、B at the period of 27-50 months. Based on the pruning trial of Corymbia Torelliana at South China Experiment Nursery, the pruning effect on wood qualities were research. The results showed that:(1)The pruning wounds started to reduce on 3 month after pruning, it reduced significantly on 7 months; some of the wounds width had become to 0 on 9.5 months, especially the large wounds recovered from>25mm to 0-5.5mm; the small and large wounds recovered 84.71% 1 year later. (2)The occlusion and complete occlusion ratio of pruning treatments after 1 year later, middling wounds is 7cm and 6cm treatments; big wounds is 7cm and 5cm treatments; large wounds is 8cm and 6cm treatments.(3)The wound treatments with painting urushi more to promote healing than waxing.(4)The higher the wound position the quicker recovering. The fastest trunk of complete occlusion ratio is 2.5-4.0m for middling wounds; it is 2.5-5.35m for big wounds and large wounds.The trials of fertiliser affect on wood properties had been researched, the results showed that, the fertiliser amount of treatment 1 and 2 were 2 or 3 times more then treatment 5 as normal fertilser application, but the wood properties of bending strength, diametric hardness and basic density of sapwood were significantly decreased at the age of 198 months, but other wood properties such as hardness of other sides, elastic modulus, shrinking rate, drying shrinkage, basic density of heartwood were tested and no significant change found.更多还原