油松对松毛虫危害的反应

为弄清油松对松毛虫危害有无自控能力，利用植物的生态控制力防治松毛虫，减少浓药的用量，采用蒽酮分光光度法测定不同失叶强度下油松干基糖分含量，结果表明：在人工模拟摘叶和松毛虫自然危害条件下，油松具有补偿和超补偿能力；在２—３年生针叶失叶较多的情况下，油松可将干部贮藏的营养物质供一年生针叶的正常生长。即使在连续三年２—３年生针叶失叶较多的情况下，油松也不致死亡，仍能正常生长。     

油松大树移栽复壮技术初探

结合油松的生物学特性、生态习性和太原市森林公园的自然条件,对移栽油松大树采取了土壤改良、针叶上喷洒生长调节剂等复壮措施。两年后观察：经复壮处理的油松生长量明显增长,且树冠针叶生长势良好,复壮效果显著,值得在移栽油松时大力推广。     

重金属Cu胁迫对油松苗木生长的影响

通过盆栽试验,模拟不同浓度铜离子胁迫条件,对1年生油松苗木的针叶含水量和光合色素含量进行了研究。结果表明:施加外援铜离子对油松生长影响显著,随着铜离子胁迫程度的加深,苗木针叶含水量和光合色素呈现下降趋势,生长和光合作用受到严重抑制,叶绿素含量与苗木生长状况的变化是一致的。     

杉木中龄林树冠叶面积密度空间分布及季节变化

对江西大岗山１７年生杉木人工林树冠内不同年龄针叶面积（ＮＡ）、叶面积密度（ＮＡＤ）的垂直、水平和二维空间分布以及当年生针叶面积及其密度分布的季节动态进行了测定和模拟。结果表明,生长盛期杉木单个树冠平均ＮＡ 为２５．４２ ｍ ２,平均ＮＡＤ为２．２７２ ７ ｍ ２·ｍ － ３,其中２年生及其以上老叶（简称２年生）大于１年生,１年生大于当年生。ＮＡＤ 的水平和垂直分布均可用β分布函数表达,而相对冠高和冠径的二次趋势面表达式可很好地描述ＮＡＤ二维空间分布。树冠内ＮＡＤ在冠中上部枝的中前部最大,但不同年龄ＮＡＤ的分布不同,当年生针叶更接近于树冠顶部和最外层,１年生针叶最大ＮＡＤ位于树冠中部枝的中前部,２年生针叶最大ＮＡＤ出现于树冠中下部枝的中部。随着林龄的增加,累积叶面积指数降低,ＮＡ在树冠中的垂直分布重心向上移动。当年生针叶干质量和ＮＡ 的季节生长进程适合Ｌｏｇｉｓｔｉｃ方程。生长末期树冠内平均ＮＡ 和ＮＡＤ可达２９．４２４ ３ ｍ ２和２．６３０ ７ ｍ ２·ｍ － ３。     

杉木对粗鞘双条杉天牛危害的补偿作用初探

植物在受害虫危害后,普遍表现出一种补偿和超补偿作用,国内外在这方面都有过研究。我国的夏乃斌、周章义、李镇宇、许志春等人研究,发现油松针叶适度受害后,在材积和营养物质储存方面都表现出补偿和超补偿现象,是以光合产物总量增加为基础。王世绩等人在研究杨树天牛...     

马尾松树针叶立体分布和模拟为害对树木生长影响的研究

１９９３￣１９９４年，对马尾松树进行调查研究后表明，１株１５年生松树针叶平均鲜重为２１１８ｇ，其外层１年生针叶占总重数６１％，内层２年生针叶占总重数３９％，１￣３轮枝叶占２５％，１￣４轮枝叶占７５％；针叶被害２５％时，留４轮枝叶可承受松毛虫１９条，是留３轮枝叶的２．４倍。     

美国白松生长特性的研究

以山东乡土针叶树种油松和黑松作对比,研究了从美国引种的１２年生美国白松的物候期及新梢、针叶的生长特性。以Ｌｏｇｉｓｔｉｃ方程拟合３种针叶树新梢和针叶的生长,并用数学分析的方法确定各树种新梢和针叶的速生期和速生点。测定了３个针叶树种的径、高年生长量。结果表明,美国白松在山东能够正常生长发育,生长期比油松和黑松短,但生长迅速,年生长量比较大,是一个值得引进并扩大栽培的速生针叶树种     

油松新生叶与老叶光合功能的比较

对油松当年生幼叶、当年生成熟叶、1年生老叶和2年生老叶的生理参数与光合效率进行测定的结果显示,不同叶龄的油松针叶叶绿素含量差异较大,其中1年生针叶的叶绿素含量最高,当年生幼叶叶绿素含量最低;随着叶龄的增大,叶绿素a/b逐渐下降。针叶蛋白质含量变化规律与叶绿素类似,但变化幅度较小。用叶绿素荧光技术探测了不同叶龄针叶的光合能力发现,当年生成熟叶的光合效率最高,1年生老叶光能捕获效率(TRo/CSo)、电子传递效率(ETo/CSo)以及功能指数(PI)略低于当年生成熟叶;2年生老叶的光合效率虽然急剧下降,但仍高于幼叶,说明幼叶还未发育成熟,光合功能还不完善。2年生老叶光合功能下降的原因主要是由于叶片质体醌库(Sm)和反应中心密度(RCs/CSo)减小,同时叶绿素含量和蛋白质含量下降所引起。这说明对油松生长贡献最大的是当年生成熟叶和1年生针叶,其次是2年生老叶,幼叶贡献最小,油松针叶的光合功能可维持3年。     

干旱处理对侧柏和油松幼苗针叶生理变化的影响

以1年生的侧柏和油松幼苗为研究对象,研究了不同方式干旱胁迫对幼苗的针叶细胞膜透性及丙二醛含量的影响。结果表明:随着干旱程度的加剧,侧柏和油松幼苗的针叶细胞膜透性呈逐渐上升趋势,后期上升幅度较大;丙二醛含量出现先降低后上升的趋势。两种树苗的指标变化都以油松最好。     

辽西半干旱地区红松引种试验研究

为有效地增加辽西地区的造林树种,更好地发挥森林多功能效应,凌源市欺天林场于１９７６年由辽东引进了２年生红松苗木造林。经试验观察,２６年生红松平均树高３．７３ｍ,胸径６．５ｃｍ,单株材积达０．００８９ｍ＾３,三项指标均超过同年栽植的油松,而且２０ａ后表现出明显的生长优势,并具有较强的适应性和抗逆性。该树种的引种成功,为辽西半干旱地区增加了一个造林树种。     

The relationship between the needle age and the growth rate in Scots pine (Pinus sylvestris): a retrospective analysis by needle trace method (NTM)

Variation in annual radial and height increments (RI and HI, respectively) as well as the number of needles belonging to different needle sets of successive annual shoots, determined by the needle trace method (NTM), was studied retrospectively in Scots pine stands, one in southern Finland and two in Estonia. The connection between different needle sets and tree growth was studied by correlation and covariance analyses. The numbers of needles of the three youngest needle sets were positively correlated with growth, whereas the number of needles older than 3 years had no significant correlation. The covariance analysis emphasized the negative relationship of older needle sets with tree growth. It is generally concluded that the two or three youngest needle sets are important and all older needles minimally contribute to growth, possibly because of their small quantity. Older needles may remain on the tree if assimilation is impeded for some reason, e.g. due to premature loss in the two youngest needle sets. The trees having attached old needles grew less than those that had already totally lost these needle sets.     

The effects of long‐term exposure to simulated acid rain on the development of pine wilt disease caused by Bursaphelenchus xylophilus

To elucidate the synergetic effects of acid rain on the development of pine wilt disease, we measured the sap flow rate in the stems and the chlorophyll content in the needles of 10‐year‐old Japanese black pine trees, Pinus thunbergii and 12‐year‐old Japanese red pine trees, Pinus densiflora, after exposure to simulated acid rain (SAR, pH 3) or tap water (TW, pH 6.3) as a control. The heat pulse method was used for the estimation of the sap flow rate. No apparent difference was found in the sap flow rate between the trees exposed to SAR and TW, but the chlorophyll content of needles at the end of the treatment was significantly higher in the trees exposed to SAR than in those exposed to TW. When the pinewood nematode, Bursaphelenchus xylophilus, the causal agent of pine wilt disease, was inoculated onto the Japanese black pines that had been exposed to SAR repeatedly for 1 year, the period to death was shortened. Japanese red pines that had been exposed to SAR for 2 years, however, did not show any development of symptoms after the nematode inoculation, suggesting that acid rain only affects pine wilt disease slightly, if at all.     

Morphology and rooting of shoots developing in response to decapitation and pruning of Caribbean pine

The effects of decapitation at various levels, combined with heavy pruning of remaining branches, were examined for Caribbean pine. This treatment stimulated the development of shoots with long primary needles at all levels in the crown of trees aged one, four and eight years. Although a significant positive relationship between primary needle length and rooting was demonstrated, the very juvenile appearance of these shoots was not a reliable guide to rooting. There was an over-riding effect on rooting of the ortet age × level in crown × decapitation height treatment. Decapitated trees provided shoots of higher rooting capacity than intact trees for the one and four, but not the eight year old trees. Shoots developing in the lower crown in response to decapitation and heavy pruning of four year old trees displayed a high level of rooting-equivalent to that of shoots from the decapitated and pruned one year old trees.     

Inter-specific competition and management modify the morphology, nutrient content and resorption in Scots pine needles

Influence of tree-to-tree competition on nutrient resorption is still not well understood. To contribute filling this gap, we assessed the effects of thinning (0, 20 and 30 % extraction of basal area) and canopy type (beech–pine vs. pine subplots) on needle dry weight, needle length, nutrient content and nutrient resorption (N, P and K) in Scots pine (Pinus sylvestris) needles of different cohorts, 8–9 years after thinning. Thinning and canopy type often concurrently affected needle morphology (e.g. lighter and shorter needles in 30 % thinning, heavier and longer needles in pine canopy on the first year of study) and nutrient content (e.g. decrease in N, P and K in 30 %; N, P and K higher in pine canopy on the first year of study). However, effects of thinning appeared only in older cohorts for N and P but were found in old and new cohorts for needle dry weight, needle length and K, indicating that some thinning effects remained after 8–9 years. Canopy effects on morphology and nutrient content were more frequent in recent cohorts, in relation to an increase in beech cover over time. While no clear effects of thinning on the nutrient resorption were observed, higher values were observed in the pine than in the mixed canopy, which could be related to a higher Scots pine stem growth in those patches. The observed differences between treatments will likely increase as the stand develops, probably leading to beech trees being dominant, and as future thinnings are carried out.     

A comparison of needle retention on Japanese black pine and Japanese red pine

Needle retention (number of needle sets), needle density, height increment and radial increment were surveyed on seven Japanese black pines (Pinus thunbergii Parl.) and seven Japanese red pines (Pinus densiflora Sieb. et Zucc.) growing on the same site. Number of needle sets on branches with respect to whorl position was estimated visually. In 1999, maximum summer needle retention was observed on the fifth and sixth whorl from the top, with values of 3.4 needle sets for the black pines and 2.4 needle sets for the red pines, respectively. The needle trace method (NTM) was used to determine needle retention and needle density along the main stems retrospectively for the years 1968–1998. The long-term mean summer needle retention along the main stem was 3.7 needle sets for the black pines and 2.2 needle sets for the red pines. In both pine species, the number of needle sets varied from year to year. However, the long-term budget between newly born and annually shed needle sets was in equilibrium. The long-term average of needle density per cm of stem shoot was 9.4 needle pairs for the black pines and 7.4 needle pairs for the red pines. The results showed clear intra-specific and inter-specific similarities in needle retention, height increment and radial increment trends. The values for number of needle sets, height increment and radial increment positively increased with favorable growing conditions, whereas the value of needle density had an opposite tendency.     

Cattle grazing and pine survival and growth in subterranean clover pasture

When combining pines and cattle on tame pasture, grazing is often delayed for several years until trees are large enough to resist injury. As an alternative approach to delayed or deferred grazing during the early years, this study in central Louisiana, USA, examined the effects of cattle grazing in subterranean clover (Trifolium subterraneum L.) pastures on slash (Pinus elliottii Engelm.) and loblolly pine (P. taeda L.) seeding survival and growth during the first 3 years of tree establishment. Pines were planted at about 1200 trees/ha in 3 rows on 0.4-ha subclover units with 1.3 m spacing within rows. Three grazing treatments included: (1) ungrazed pines, (2) limited grazing with a single-wire electric fence above the planted pines, and (3) grazed pines. Thirty Brahman crossbred cows with calves and a bull grazed the tame pasture on a controlled grazing, rotational basis from December through May each year, during the subterranean clover growing season. Pine trampling injury during the year was 8% on the grazed seedlings while essentially none occured under limited grazing. During the first 2 growing seasons, survival and height of the pines were significantly less on the grazed seedlings than on either the limited grazing or ungrazed seedlings. Pine heights from the limited grazing and ungrazed treatments were not different during the 3-year study; loblolly pine heights from the limited grazing treatment continued to be taller than the grazed treatment through the third year while the slash pine heights were similar for all treatments by the third year. Seedling mortality became more acute as severity of grazing injury increased; the greatest mortality occured when the terminal bud and needles were both browsed off.     

Influence of silvicultural practices on twisting rust infection and damage in maritime pine,as related to growth

A three-year study was carried out on the influence of silvicultural intensification on infection and damage caused by Melampsora pinitorqua, the twisting rust fungus, in maritime pine, Pinus pinaster Ait. The silvicultural practices studied were phosphorus fertilisation, the mode of stand establishment (either seeds or plants), and pine density. Growth and nutrition variables were also measured. Infection and damage were the most important in the first two years, which could reflect higher resistance with aging. At the end of the experiment, when pines were 4 years old, the planted, fertilised pines turned out to be the most damaged and the tallest, while the sown, non-fertilised pines were the least damaged and the smallest. Final damage was mainly explained by the damage observed in the earlier years. Annual damage was significantly correlated with infection percentage, more closely in the first year of observation. Higher susceptibility of the planted pines was associated with better growth and was explained by a greater amount of susceptible tissues, Under our experimental conditions, this explanation could not be retained for the fertilisation effect. However, phosphorus fertilisation induced changes in the nutritional status of pines. A significant positive correlation was observed between the phosphorus and potassium content on one hand and the susceptibility and damage on the other hand. Density effects were seldom observed in the experiment, either on growth or susceptibility variables. The positive relation between pine growth and rust damage, as confirmed in this study, emphasises the need for an integrated management of intensively managed pine stands, taking into account the disease hazard.     

Changes in the canopies of Pinus sylvestris and Picea abies under alkaline dust impact in the industrial region of Northeast Estonia

Studies were carried out in 1999, 2005 and 2007 in the area of Kunda cement plant in Northeast Estonia on sample plots 3 km W and 2.5 and 5 km E of Kunda. As control stands, two plots for pine and spruce were established in Lahemaa National Park (34-38 km W of Kunda). The selected pine and spruce stands were 75-85-year-old Myrtillus site type, of 0.7-0.8 density and II quality class, with moderately dense or sparse understorey. The values concerning needle density and number of needle scars were higher for shoots formed in the period of higher pollution than for the shoots grown under a considerably lower pollution load. Although the cement dust pollution has notably decreased from year to year, the number of needle pairs per 1 cm of the shoot was 1.8-2.1 times greater in the shoots formed in 1998 than in those formed in 2003, whereas the changes were statistically reliable. Possibly the low temperatures at the time of shoot and needle formation affected the density of needles on all sample plots, and thus the number of needles on shoots formed in 2003 was many times smaller. After the significant fall in the pollution load since 1996 the length growth of needles intensified around Kunda cement plant, at the same time no changes occurred in the length growth of needles in the control area. As compared to the data from 1998, the length growth of pine needles had improved, especially 2.5 and 5 km E from the cement plant, needles being respectively 1.5 and 1.1 cm longer than 6 years ago. The stimulation of the growth of pine and spruce needles 2.5 and 5 km E of the cement plant may be a sign of a positive effect of reduced doses of cement dust in soil. The greater length of pine and spruce needles is the reason for the larger biomass of the needles.     

思茅松松材线虫病症状初步研究

思茅松是松材线虫在自然条件下感病的新寄主植物,对思茅松天然林区症状观察的同时进行了室内人工接种试验观察,结果表明,在思茅松上松材线虫病的症状表现与其他寄主上的有所不同,即松针当年陆续脱落和感病中期还有流脂现象。