Effect of edge stands on the development of young Pinus sylvestris stands in southern Finland

Abstract

The quantitative effect of pine-dominated edge stands in southern Finland on the density and growth of pine saplings was addressed in the study. The cumulative effect of a mature edge stand on the development of a pine sapling stand with variable cutblock sizes was also estimated. The data were acquired from 10 study sites with a Scots pine sapling stand with a current dominant height of 1–6 m and an adjoining middle-aged to mature edge stand dominated by Scots pine. Tree level models were constructed to describe and simulate the structure and development of the sapling stands. The results indicated that dividing an average regeneration area (2 ha) into smaller cutblock units (1.0–0.5 ha) appreciably increased the edge stand effect. Total stand volume growth was 6% lower on 1 ha cutblocks, and 31% lower on 0.5 ha blocks, than on 2 ha blocks.     

Structural development of pinus sylvestris stands with varying initial density: A simulation model

The growth and structural development of Scots pine (Pinus sylvestris L.) trees growing at different spacing was simulated using a model based on the dry matter production per needle biomass unit and its allocation to needles, branches and stem. Special emphasis was given to the effect of stand density on the growth of the crown system and its implications on branchiness and timber quality. The simulations showed that the needle biomass culminates considerably earlier than the branch biomass with a time lag inversely related to the stand density. The lengths of living and dead crown were also inversely related to stand density. The resulting differences in branchiness were especially obvious in the early development of the tree stands. In the long run these differences tend to disappear, indicating equal external branchiness independently of the initial spacing for mature stands of Scots pine. The internal branchiness, however, was particularly sensitive to the initial spacing.     

Canopy density in stands of Picea abies and Pinus sylvestris after different thinning methods

Altogether 82 plots (261 estimations) of Picea abies (L.) Karst, and 193 plots (360 estimations) of Pinus sylvestris (L.) stands were estimated by a vertical tube. The “crown free projection”, CFP, of stands thinned in three methods with different thinning grades was measured: unthinned, heavily and very heavily thinned, heavily thinned delayed first thinning, extra heavily thinned and thinned from the top. Basal area (m²ha^?1) density (stems ha^?1) and diameter sum (m ha^?1) were plotted against CFP. Basal area was the best practical measure of stand in this study. Generally Scots pine stands have higher CFP and the curves are steeper than in Norway spruce stands. Depending on the grade of thinning, heavily and very heavily thinned spruce stands, delayed first thinning included, have CFP values of 10–15% and stands thinned from the top, 20–40%, compared with 30–80% and 30–60% respectively in pine stands. Extra heavily thinned stands have the highest CFP, 20–80% in spruce and 50–90% in pine stands. The CFP levels after thinning are too high in pine stands for avoidance of sucker and sprout production of aspen and birch. In dense Norway spruce stands thinned from the top or heavily and very heavily thinned, the CFP values are low enough (≤30%) to diminish the production of suckers.     

天然长白松干形的研究

长白松是我国特有的松科松属植物,仅见于长白山海拔630~1 400 m之间,因其特殊的分类地位和优良的遗传性而受到普遍关注。本文对第一代天然长白松林的干形进行了分析研究,结果表明:正形数的变动系数最小,相对比较稳定;从正形率系列看,q0.7以下的变动系数均小于10%,随着直径上移,变动系数增大;形数随形率增大而增加,且相关关系紧密;利用样条函数理论,拟合出长白松干形曲线的样条函数方程组,利用计算机程序可容易地计算出立木材积,与实测值相比较80%样木的误差小于3%,精度较高。海拔700 m处的长白松立木干形优于海拔1 100 m处的干形,尖削度小,干形圆满,出材率高。     

Distribution and yield of biomass from young Pinus sylvestris and Picea abies stands on drained and fertilized peatland

Above‐ground biomass has been measured on fertilized and control plots up to stand age 31 years. Each biomass fraction was estimated by two statistically coupled linear models with squared diameter at breast height as independent variable. All fractions except reproductive structures of pine and dead branches of spruce were estimated at high precision levels, R. between 0.93 and 0.99. The above‐ground biomass fractions per hectare could be precisely described by stem volume with bark. Application of the models for prognostic purposes is discussed. Annual above‐ground net biomass production in pine increased from 2.05 to 4.34 MT d.m./ha‐yr on control plots over 11 years, while plots given complete fertilizer mixture ranged from 6.75 to 9.09. Spruce stands with a nearly optimum water relationship and fertilizer programmes yielded from 9.50 to 11.86 MT d.m./ha‐yr. The combination of energy and timber production in highly productive peatland stands is discussed.     

Identifying the biological effects of pre-commercial thinning on diameter growth in young Scots pine stands

Data from seven Scots pine (Pinus sylvestris L.) stands in central Sweden that had undergone pre-commercial thinning (PCT) were used to investigate the biological effect of PCT on the diameter at breast height (DBH) growth of the remaining trees. Two treatments were considered: a PCT treatment and a control (C) with no PCT. The DBH of the trees in each stand was measured on up to four occasions over 15 years. We examined mean DBH and DBH growth of the largest 300, 600, 900 and 1200 trees ha^?1. Two methods of selecting the trees used to calculate the mean DBH values for each measurement occasion were considered: the actual mean DBH (Dma), which is based on the DBH distribution of the trees on the measurement occasion in question, and the genuine mean DBH (Dmg), which is based on the DBH distribution of the trees on the final measurement occasion of the study and therefore focuses on the same set of trees for all measurement occasions. There was no clear difference between the Dma- and Dmg-based DBH increments, but the Dmg values tended to be somewhat larger both for the C and PCT treatments. Over a 15-year period, the relative mean yearly increments (Dma/Dmg) for different tree size classes ranged from 0.91 to 0.98, with lower values for the C treatment and larger DBH size classes. We found that PCT promotes DBH growth: over a 15-year period, the increased growth amounted to about 2.0 mm year^?1 compared to the trees in unthinned plots.     

Comparison of growth and stem form characters of Pinus sylvestris clones and seedlings of the same origin in a 10-year field trial

Abstract

A field trial of cuttings and seedlings of Scots pine (Pinus sylvestris L.) was measured after 1, 2, 9 and 10 years. Growth-related and stem form characteristics of rooted cuttings were compared with those of seedlings of the same origin. The cuttings were shorter than the seedlings throughout the experiment, but the difference became smaller with age. The ranking of cuttings and seedlings by average height was already the same after one growing season regardless of the differences in planting heights of the cuttings, indicating that the genetic origin affected the height more than the initial planting height. The growth patterns of the cuttings were similar to those of the seedlings. The bole straightness and stem taper after 10 years in the field were similar in both plant types, but not stable, indicating that the use of cuttings for stem quality selection at an early age has no advantages over the use of seedlings. In conclusion, the consistent performance of cuttings compared with seedlings of the same origin indicates that performance of cuttings is a valid measure of their genetic potential and that cuttings can be used to speed up selection in breeding programmes with Scots pine.     

樟子松无性系种子园去劣疏伐技术研究

通过对樟子松无性系种子园进行去劣疏伐试验研究,结果表明:30~33年生樟子松初级无性系种子园经过2次总计30%的疏伐,郁闭度由原来的1.0降到0.75~0.79,保留180~250株·hm-2;樟子松母树单株结实量为3.89kg·株-1,比疏伐前平均提高2.98倍;种子产量为12.06kg·hm-2,比疏伐前平均提高1.00倍;种子千粒质量达8.32g,比疏伐前提高2.7%,发芽率提高25.2个百分点,发芽势提高32.5个百分点;4m×4m、4m×5m、5m×5m、6m×5m、6m×6m的樟子松种子园疏伐年龄分别为22a、24a、26a、28a和31a。去劣疏伐使樟子松初级无性系种子园达到了去劣疏伐种子园的标准,实现了种子园的提档升级。     

欧洲赤松的引种栽培

通过欧洲赤松30年的引种试验,结果表明：欧洲赤松在小陇山林区表现出较强的适应性和生长优势.在生长、抗落叶病性状上优于乡土树种油松.麦积植物园30年生欧洲赤松平均树高、胸径分别达13.60m和22.8 cm,生长量与乡土树种油松相当.已完成从种子到种子的引种过程,欧洲赤松在甘肃小陇山引种获得成功.     

樟子松苗木沙培试验施肥效应

通过采用正交施肥设计在温室进行沙培试验,并作田间施肥试验,建立樟子松S1-1苗木根干重、新梢干重和全干重与N、P的函数方程,并通过该方程求出适宜施肥量:N为0.67g/L,P为0.04g/L。     

樟子松人工林枝条生长规律的研究

根据标准地和解析木调查资料,以樟子松人工林树冠内活枝为研究对象,探讨同一树木的不同龄阶的枝生长规律,同一林分不同大小树木枝生长的规律,以及不同林分条件下枝生长的规律。结果表明:单株树木枝条长度总生长曲线呈"S"形,连年生长在生长初期达到一最大值后随年龄的增加而逐渐减小;在同一林分中,枝条总生长随着枝龄的增加而持续增长;在不同年龄相同密度林分中,年龄较小的林分枝长连年生长要比年龄较大的树林增长快一些;在相同年龄不同密度林分中,密度较小的林分比密度较大的林分枝长总生长及同期连年生长要快一些。     

不同生物控制技术对樟子松林分生长及松枯梢病发病程度的影响

通过对樟子松林分进行生物控制技术的研究可知,在中龄林进行施用菌剂、切根、人工整枝试验对促进樟子松树势的恢复、树木胸径生长、增强树势等方面等有明显作用:在胸径生长方面,3个处理与对照差异显著,其中切根5年后的樟子松林分胸径生长高于施用菌剂和人工整枝处理,年生长量达1.89cm;3个处理与对照相比,大大减少了松枯梢病发病机率,其中修枝处理防控病害的效果最好。     

Comparison of the cost and energy efficiencies of present and future biomass supply systems for young dense forests

The objective was to study the effect of future harvesting and handling technologies on the cost and energy efficiency of supply chains for young dense thinnings. The system costs and energy requirements were modeled using type of stands, products delivered, and transport distances as variables. In total, 14 systems were analyzed, of which five represented future systems. The effects of increasing the payloads of off-road and road transportation of whole tree (WT) parts by 10%, 20%, and 30% were also analyzed. If boom-corridor thinning technologies, optimized bundle-harvesters, and load-compression devices are developed, on average, costs are reduced by 12–27% and 11–30% less energy is required when compared with present systems. For example, at an average harvested tree size of 22 dm³, the supply of WT using future technologies would reduce the cost by up to 15% and the energy requirements by 21%. These effects increase with reduced tree sizes and increased transportation distances. The effects of future technologies are especially significant for tree sizes below 30 dm³, representing a significant part of the potential that could be harvested annually in Sweden. Thus, there should be increased research and development of boom-corridor felling technology, bundle-harvesters, and load-compression devices.     

Survival and strobili production in topgrafted scions from young Pinus sylvestris seedlings

Abstract

Reducing the generation turnover increases the genetic gain in a breeding programme. Topgrafting, new genetic material being grafted into the crown of ramets of reproductive mature trees, can deliver this aim since it is able to induce strobili production in young material of conifers. To this end, I studied the effect of scion age (seedlings of 4–6 years from seed) on topgraft vitality/survival, and female and male strobili production in Pinus sylvestris (L.) over 5 years. The seedlings' growing environment prior to topgrafting had a significant impact on topgraft vitality, with more vital topgrafts obtained from potted seedlings than from seedlings grown in raised nursery beds. However, the growth environment had no clear effect on female or male strobili production. In the second year, after grafting up to 76% of the topgrafted seedlings had female strobili. Vitality increased with age of the seedling from which the scions were collected, but differences in both female and male strobili production were only marginal. The position of the topgraft within the interstock crown influenced both vitality and strobili production, with higher vitality and greater male strobili production in low positions and greater female strobili production in high positions. Based on these results, breeders should perform topgrafting as soon as the seedlings have enough scions for planned crossing activities.     

樟子松人工林树高生长对气候因子的响应研究

为了确定气候因子对樟子松人工林树高生长的影响,为以后的樟子松人工造林和经营管理提供科学的依据,本文通过对内蒙古凉城县蛮汉山林场樟子松人工林进行调查,利用蛮汉山林场樟子松6块标准地调查的解析木数据,结合凉城县气象站多年的气象资料,采用因子分析法和回归分析法研究了樟子松人工林树高生长与气候因子的关系。研究结果表明：影响蛮汉山樟子松人工林树高生长的气候因子顺序是：年平均风速（x6）〉年平均湿度（x5）〉年降雨量（x4〉年极低温度（x3）〉无霜期（x7）〉年平均气温（x1）〉年极高温度（x2）;年平均风速（x6）和年平均湿度（x5）是影响蛮汉山地区樟子松人工林树高生长的两个主导气候因子;通过主成分分析,进一步得知水分是影响该地区樟子松人工林树高生长的关键因素;最后建立了樟子松树高连年生长量与气候因子之间的数学回归模型。     

Tap root formation and early root/shoot ratio of Pinus Contorts and Pinus sylvestris

Scots pine and different provenances of lodgepole pine were compared in regard to root characteristics and the distribution of biomass within individual trees. Tap root formation was more frequent and the root/shoot ratio was higher on Scots pine than on lodgepole pine but significant variation of these traits was found between provenances of planted lodgepole pine. A non‐destructive method for estimation of root biomass was developed.     

木兰围场陡坡地段油松与樟子松造林生长状况比较研究

通过对木兰围场陡坡地段油松与樟子松造林存活率与生长状况进行的比较研究,结果表明:(1)2种林分中油松存活率较高,达93.01%,樟子松存活率为86.34%,二者的存活率均处于较高的水平;(2)樟子松人工林的平均地径较大,达5.51cm,而油松人工林地径较小,为4.82cm;(3)樟子松人工林的平均树高较大,达182cm,而油松人工林平均树高较小,为161cm。木兰围场陡坡地段环境更有利于樟子松的树高生长。     

Variation in nutrient concentrations of Pinus sylvestris stems

Spatial and temporal variation of N, P, K, Ca, Mg, Mn, Zn, B and Al concentrations in Scots pine (Pinus sylvestris L.) bark and stemwood was studied in three stands at different stages of development. Concentrations of the mobile nutrients N, P and K increased in stemwood and inner bark towards the youngest tissues vertically towards the top of the stem, and horizontally from the pith to the youngest annual rings. The concentrations of Ca, Mg, Mn and Zn were greatest in the oldest tissues and decreased horizontally towards the youngest annual rings. There was a slight increase of most nutrients near the divide between sapwood and heartwood. Seasonal nutrient variation was greatest in the inner bark. The highest nutrient concentrations occurred in winter and spring. Concentrations also varied with stand age, especially in the inner bark, being lowest in the oldest stand.     

沙地樟子松生长规律的研究

通过对内蒙古红花尔基林业局经营的沙地天然樟子松的生长特别和分布规律的研究,结果表明:沙地樟子松生长在不同光照条件和不同密度的环境下,林木的高生长和胸径生长存在很大的差异,樟子松在疏林(0.3~0.5)时,高生长快,胸径生长正常,材积生长数高。