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.     

云南松纵坑切梢小蠹示范林综合治理

１９９２～１９９５年在云南省玉溪市北城镇刺桐关办事处石狗头村，对遭受云南松纵坑切梢小蠹危害严重的３３４ｈｍ２云南松林，进行了营林防治技术、害虫种群防治技术等综合治理措施示范和研究。通过４年的综合治理，示范林被害株率由防治前的６２．６７％下降到３．７２％，下降率９４．０６％；蠹害指数由３３．３０下降到１．２９，下降率为９６．１％；对照林地３４ｈｍ２的被害株率由３９．０３％，上升到９０．４７％，上升５６．８５％；蠹害指数由２０．１０上升到４７．２２，上升率为５７．４３％。挽回经济损失３０．７９万元，提高了云南松林的经济、社会、生态三大效益，取得明显效果。     

Comparison of greenhouse and environmentally controlled growthroom root growth potential testing of 2+0 eastern white pine seedlings

Two-year-old estern white pine (Pinus strobus L.) seedlings were measured for Root Growth Potential (RGP) in a hydroponic system over two years in both a greenhouse and an environmentally controlled growthroom. Analyses of variance showed no significant differences (alpha = 0.05) between testing environments for either year. This study demonstrates the validity of using greenhouse RGP testing for 2+0 eastern white pine.     

马尾松与黄山松天然杂种种群特性探讨

江西庐山、九岭山在黄山松垂直分布下界,发现有马尾松和黄山松的自然杂交种,通称“杉松”。其实,其叶内树脂道边生和中生兼有,且性状稳定和黄山松有质的区别。因此,我们把它拟定为新种,命名庐山松(学名待定)     

油松种子园结实技术研究

本文通过对油松球果生命史的调查,掌握了油松球果在其生长发育过程中的损失情况。提出了一整套促进油松种子园种子丰产的综合技术,使良种产量由原来的平均11．5 kg／hm2提高到26．0 kg／hm2。     

Black polyethylene mulch improves growth of plantation-grown loblolly pine and yellow-poplar

The effects of mulching with perforated black plastic, in combination with fertilization and induced mycorrhizal symbioses, on the growth of loblolly pine (Pinus taeda L.) and yellow-poplar (Liriodendron tulipifera L.) were studied in a plantation under intensive, short rotation management. Mulching effects on soil temperature were also examined in order to assess the potential influence of this treatment on temperature-dependent processes in soils affecting tree growth. Mulching significantly increased height and stem diameter growth of both species, attributable largely to improved water relations resulting from diminished soil surface evaporation and elimination of transpirational losses from competing vegetation. Mulching effects on soil temperature were insufficient to contribute substantially to the growth response exhibited by mulched trees. Multiple applications of urea-N promoted enhanced growth in both loblolly pine and yellow-poplar, an effect accentuated by mulching, but the field performance of trees inoculated in the nursery with selected mycorrhizal fungi was poor relative to that of the other treatments investigated.     

Soil and foliar phosphorus as indicators of sustainability for Pinus radiata plantation forestry in New Zealand

We investigated how multiple-crop forestry has influenced the magnitude and variability of soil and plant phosphorus (P) fertility and site disturbance. Kinleith Forest, on Mamaku Plateau, covers >100,000 ha and comprises mainly plantation Pinus radiata. Three study areas in the forest were chosen to represent natural state (native forest), first crop of P. radiata (24 years growth), and second crop of P. radiata (4 years growth of second crop). The adjacent areas have similar relief and climate, and the soils are all the same age, being predominantly Andic Haplohumods developed in 1770 calendar-year-old non-welded tephra (Taupo Ignimbrite, ca. 0.5–0.8 m in thickness) and overlying a buried paleosol on earlier tephric material.

Soil properties were compared using a random geometric sampling scheme stratified in a 40-m grid. Soil samples (0–20 cm) were taken at 1.5, 4.5 and 13 m spatial intervals in random directions away from each primary node, providing 192 sample sites for each study area. Additionally at selected sites, samples of the current year's foliage from the upper crowns were collected, the thickness of Taupo Ignimbrite (i.e. depth to buried paleosol) was recorded by augering, and site disturbance was assessed using a new six-point scale based on change relative to a modal soil profile. Geostatistics and geographical information systems (GIS) were used to assess variability and effects of forest management on the measured properties. Soil Bray-2 P concentrations were below guidelines for satisfactory growth (12 mg kg⁻¹) at all sites, and no differences were recorded between the different management areas. However, the amount of within-site variability in Bray-2 P increased with the number of crops. Foliar P concentrations were only marginally deficient in both the first and second crops, indicating that P is currently not significantly limiting growth. The lack of difference in foliar P between first and second crops indicates no crop-to-crop decline in foliar P status and suggests that no site P fertility decline has occurred. The soils have an unusual ability to continue releasing P through successive sequential extractions in the Bray-2 P test, indicating a strong buffering capacity, and this may explain the apparent lack of deficiency even with Bray-2 P values of <12 mg kg⁻¹. The site disturbance index increased and the spatial distribution of P data became increasingly variable with crop rotation.

GIS, inverse-distance weighting and kriging proved useful in illustrating the trends between crops. The spatial variability of results indicated that there was no obvious pattern to the variability and that more site-specific forest management in the region would be difficult. However, there was some evidence that less disturbance during harvesting may minimise variability of soil P supply.     

Anatomic Study of Female Sterility of Pinus tabulaeformis Carr.

The anatomic research on the mutant clone of Pinus tabulaeformis Carr.in the seed orchard in Xingcheng,Liaoning Provinces was carried out.The female cone of the mutant clone looked like normal,but its ovules degenerated in early stage.This paper trics to find out the reason and time of ovule abortion.It seems that the ovule abortion is probably caused by female sterility because the microspores of this mutant clone were normal.Through the serial observations on the one-year-old macrosporangiates and the ovules of two-year-old female cones of mutant and normal clone,it is found that the reason of ovule abortion in mutant clone is the failure of the mitosis of free nuclei in the female gametophyte,and the time is about in the early April.     

Artificially regenerating longleaf pine in canopy gaps: initial survival and growth during a year of drought

Nitrogen fertilization in the nursery, along with altering the configuration of forest gaps, may improve the reforestation success of longleaf pine seedlings. During the very droughty 1998 growing season in Florida and Georgia, survival was higher under the forest canopy than in small (0.10 ha, 36 m diameter) and large (1.6 ha, 144 m diameter) canopy gaps. In the large gaps, survival of containerized seedlings was higher along the edges, particularly the SW edge. Shade from adult trees and the nurse effect of shrubs increased survival, while grass competition reduced survival. During dry years part of the “exclusionary zone” along the edge of canopy gaps (SW sector) may serve as a “survival zone”, at least in the short term. A model using oval-shaped gaps oriented from NW to SE, with an area of 0.25 ha is proposed to maximize the survival and growth of artificially regenerated longleaf pine seedlings.     

长江中上游马尾松水土保持林生长过程模型研究

将乔木、灌木和草本层次结构合理、郁闭度为0．68左右，蓄水固土功能最优的林分定义为马尾松水土保持林的优良林分，从制表单元、编表样本、模型建立到数表编制，系统地论述了长江中上游马尾松水土保持林优良林分生物量生长过程表的制表过程．为长江中上游水土保持林的经营提供了决策依据．