幼林抚育对核桃树生长的影响

通过核桃幼林中耕除草与未中耕除草、间作与未间作对比试验,探索了核桃幼林抚育对核桃生长的影响。结果表明:中耕除草桐林的成活率以及树高、地径生长都比未中耕除草桐林有所增加,1次中耕除草效果差,中耕除草2～3次效果最好。间作薯类、豆类及谷类的核桃生长量比未间作的都有所增加,以间作薯类和豆类效果最明显。     

幼林抚育对油桐生长影响的试验研究

为探索幼林抚育对油桐生长的影响，通过油桐幼林中耕除草与未中耕除草、间作与未间作对比试验。研究结果表明：中耕除草桑林的成活率以及树高、地径生长都比未中耕除草桐林有所增加，1次中耕除草效果差，中耕除草2～3次效果最好。间作薯类、豆类及谷类的油桐生长量比未间作的都有所增加，以间作薯类和豆类效果最明显。     

板栗幼林间作管理技术研究

板栗幼林间作西瓜、马玲薯试验表明 ,间作林的土壤有机质、有效P、水解N含量均比人工抚育林、化学除草林的高 ;间作农作物能显著提高栗树生长 ,提早投产时间 ,增加经济效益     

丰产杨树的培育

1中耕除草结合间作 适时进行中耕除草，杨树林地间作应以接秆作袖为主．如豆类、花生等．     

杨树速生丰产林栽培管理

1.中耕除草结合间作.适时进行中耕除草.杨树林地间作应以矮秆作物为主,如豆类、花生等. 2.灌溉施肥.5月下旬至8月下旬是杨树材积生长旺盛时期,土壤相对含水量应保持在70%左右.为保证杨树的快速生长,在土壤含水量低于45%时应及时灌溉,并在灌溉前追施化肥,氮、磷、钾的比例为3:1:0.5.     

须弥红豆杉幼树林农林复合经营的初步研究

为了解决须弥红豆杉幼树林无收入、抚育成本高的问题,进行了不同的间作模式试验研究,结果表明：效果较好的间作模式为“红豆杉-蚕豆-大豆”,能获得较大效益,间作植物的红豆杉幼林的树高生长高于未间作,且差异显著,依次为：红豆杉-蚕豆-大豆＞红豆杉-蚕豆-不间作＞红豆杉-不间作-大豆＞未间作;而地径则小于未间作,对当年生最长枝及发新梢树无明显差异,须弥红豆杉幼树林进行豆类（大豆、蚕豆）间作经营是一种较为理想的复合经营模式,可在适宜的区域进行推广。     

山地板栗幼林间作农作物效益的研究

1994-1999年在板栗幼林内，进行4种不同海拔高度间作农作物的试验。结果表明，在徂徕山区板栗幼林，以花生、大豆轮茬间作，可取得显著效益。     

适时科学地进行幼林抚育

人们常说:“三分造,七分管”,要想使造林获得成功,很大程度上决定于幼林的保护和抚育管理。保护得好,抚育管理得当,才能使人工林健康成长。抚育管理包括土壤管理、幼林抚育、补植等。补植要在造林后的2～3年内完成,保护则要贯彻始终。土壤管理工作有中耕除草、间作、灌溉等。幼林抚育工作包括修枝、间伐、平茬等。人工林的初期——幼林阶段,对所处环境有一     

二次结实板栗早实优质高效栽培试验

二次结实板栗是经过５年时间选育出的珍稀优良品种。通过采取夏季摘心、适时施肥、去雄疏果、中耕除草和防病治虫等技术措施,使其产量和经济效益比对照品种魁栗、处署红有明显提高,且第二次果的蛋白质、脂肪含量较高。     

刺槐幼林间作试验初报

<正>集约经营是促进林木速生丰产的重要措施。但目前一般林业单位(如国营林场、乡办林场等)单独对林木加强以水肥为主的综合管理条件不足,经济力量欠缺。1987年我场同三村分场采取幼林内间作办法,收到了明显效果。连续间作2年的地块幼林生长旺盛,每年亩地面还可收入200多元。1988年10月,我们对间作2年、1年、未间作幼林进行了调查。现将结果初报如下:     

Herbicides are more cost-effective than alternative weed control methods for increasing early growth of Eucalyptus dunnii and Eucalyptus saligna

Effective weed control is an essential management task in establishing commercial tree plantations. Much of the current weed control strategies employed in Australian forestry relies on the use of available herbicides. However, given community concern regarding the use of herbicides, investigation of alternative weed control methods is warranted. We tested the ability and cost-effectiveness of mechanical (hand weeding and inter-row slashing), mulching (sawdust over newsprint, woodchips and jute), cover crops and herbicide applications for weed control in establishing eucalypt plantations. Jute matting and herbicide treatments reduced weed competition and increased seedling growth to age 2 years in plantations of Eucalyptus dunnii and Eucalyptus saligna in northern NSW, Australia. Growth increased by 269 % (Experiment 1) and 196 % (Experiment 2) in the Jute and by 216 % (Experiment 2) in the Herbicide treatments when compared to the control (no weed control) at 2 years age. As the Jute material deteriorated, after nearly 2 years, weed cover increased and there were significantly more weeds present in the Jute treatment compared to the Herbicide treatment. Jute matting costs approximately 15 times more than the herbicide regime used and, therefore, could not presently be considered a viable option for weed control in commercial eucalypt plantations. Other weed control treatments, including hand weeding, sawdust and woodchip mulches, slashing and sowing cover crops did not effectively control weeds and did not improve survival or increase seedling growth to age 2 relative to the control. We conclude that herbicides remain the most cost-effective weed control option available to commercial growers of eucalypt plantations.     

Ground vegetation as an indicator of site quality: effect of non-site factors on the productivity of newly established chestnut plantations in northwestern Spain

The growth of 67 young hybrid (Castanea × coudercii A. Camus) and pure sweet chestnut (Castanea sativa Mill.) plantations was studied in relation to ground vegetation (GV) and non-site factors such as type of site preparation, weed control (WC), disease-related damage and prior land use. The classification and regression trees procedure was used to analyse the data. Ground vegetation communities accounted for a large amount of variability in the site index (SI) and were found to be useful as predictors of chestnut site quality. The presence of broom communities indicated the best site for establishing chestnut plantations, whereas bracken and bramble communities indicated poorer conditions, although those sites can still be considered suitable for growing chestnut. Terrain covered with herbaceous communities also indicated intermediate or even good site conditions. The poorest sites were the heathlands. As regards non-site factors, only weed control was found to be a significant variable. Ground vegetation caused a significant reduction in tree growth, indicating the importance of carrying out regular weeding to improve productivity. The most positive effect of weeding on height growth was detected in terrain covered by gorse and broom, and the least positive effect was observed in heathland. The findings are important for forest management purposes, as evaluation of ground vegetation will enable rapid prediction of site productivity classes in afforested areas and help in selecting the best land for planting this species in reforestation programmes.     

马尾松不同抚育方式对林地生产的影响

对马尾松幼林采用全面劈草、全面劈草局部松土、全面除草松土3种抚育方式对林地植被生长、表层土壤变化及幼林生长的影响进行研究,结果表明:植被覆盖率、植被枯落物随抚育强度提高而降低,而土壤侵蚀则随抚育强度提高而增强,马尾松幼林生长与抚育强度提高成正比.在南方马尾松集约经营的山区,宜提倡带状抚育,既可促进幼林生长,又能维护地力.     

淳化县渭北黄土高原花椒栽植管理技术

结合淳化县不同区域气候和地形地势等条件,提出了园地及优良品种选择、苗木处理与保护、栽植与定干等花椒栽植技术,以及地膜覆盖、施肥、整形修剪、中耕除草、病虫害防治等椒园管理技术。     

桉树人工林的防火措施探讨

分析了广西桉树人工林的火险特点,简述桉树人工林的防火措施,重点介绍造林过程中采取化学除草,既可抚育又可防火的措施。     

Toxicity of Five Granular Herbicides to Sitka Spruce and Lodgepole Pine

Experimental plots in young plantations of Sitka spruce andlodgepole pine were over-dosed with five granular herbicidesto ascertain the margin of crop safety involved in the use ofpropyzamide, chlorthiamid, dichlobenil, dichlobenil/dalaponmix and atrazine. It is concluded that if the five herbicidesare applied according to the standard rates and dates used inthe experiments, tree damage will be kept to an acceptable minimum.Better shoot growth resulted from herbicide treatment than fromhand weeding particularly where atrazine was used.     

Growth recovery of young hinoki (Chamaecyparis obtusa) subsequent to late weeding

The effects of late weeding treatment on the growth of young hinoki (Chamaecyparis obtusa) during the sixth growing season after planting were examined. Furthermore, the contribution toward hinoki growth recovery of crown productivity (NAR) and biomass allocation to crown (CAR) were determined. In the late weeding plot, no decline in height growth was observed subsequent to weeding, and growth in diameter at breast height (DBH) and crown projection area (CPA) began to recover subsequent to weeding; however, DBH and CPA were reduced and experienced a 1- to 1.5-year growth delay compared to values associated with the weeding plot at the end of the second year subsequent to weeding. Relative growth rate (RGR) and NAR in the late weeding plot recovered and possessed similar values to those of the weeding plot in the second year subsequent to weeding. CAR values of the late weeding plot were similar to those of the weeding plot both before and after weeding. These results suggested that the recovery of NAR rather than that of CAR was primarily responsible for the recovery of RGR. The present study demonstrated that hinoki were able to quickly acclimate to an environment dramatically altered by late weeding and recover growth rate within a short period of time. The present study also showed that delays in crown expansion associated with late weeding may have impeded subsequent matter production. Therefore, it was concluded that late weeding treatments should be employed only when the associated delays in growth are taken into account.     

Effects of management, environment and landscape conditions on establishment of hardwood seedlings and saplings in central Japanese coniferous plantations

There is an increasing need to restore natural hardwood forests in landscapes dominated by monocultural conifer plantations. A convenient restoration approach is to exploit natural regeneration processes. Natural regeneration, however, is affected by diverse interacting factors, for which better understanding is required, in order to optimize restoration programs. To identify optimal management practices for improving natural regeneration of hardwood trees in coniferous plantations, we examined the effects of multiple factors on the abundance of seedlings, small saplings and large saplings (height <0.3, 0.3-1.3 and ?1.3 m, respectively) of hardwood tree and shrub species in both line thinned (LT) and unthinned (UT) plantations of sugi (Cryptomeria japonica) and hardwood forests (HF) in central Japan. The effects of management practices (number of the times of weeding and cleaning, thinning method, years after thinning and forest age), environment (slope position, slope angle and canopy openness), and landscape conditions (distance from nearest hardwood forest, altitude and landuse before planting) on the number of hardwood individuals were examined by using the data obtained from the LT plantations. We also compared hardwood density between LT and UT plantations to examine the effect of line thinning. Finally, we examined species composition of LT plantations and HF to identify hardwood forest components in the thinned plantations. The effects on hardwood regeneration of environmental conditions, landscape factors and management practices applied in the plantations varied, depending on the size class and life form of the regenerating species. The abundance of large saplings of tall tree species was affected by several management factors, especially number of the times of weeding. Landscape conditions (distance from the nearest hardwood forest and altitude) affected the abundance of small saplings and seedlings of tall tree species, but not the other classes. Seedlings and small saplings of many tall tree species that contribute to hardwood forest canopies were less abundant in the LT plantations. The results show that numerous factors affect the establishment and abundance of naturally regenerating hardwood tree species, and suggest that successful establishment during early plantation stages can have long-lasting effects on natural regeneration of tall tree species.     

Early growth of pigeonpea under open-pit planting and restricted weeding in semiarid Zimbabwe

Simple and efficient tree-establishment methods are a key to the success of agroforestry technologies under limited-resource conditions. An experiment was conducted to test the effect of open pit planting and reduced weeding on soil moisture content and growth of pigeonpea (Cajanus cajan (L.) Millsp.). The results indicated that open-pit planting might reduce early growth of the plant. Clean weeding gave the most rapid growth and should be practised in the first year of establishment. However, because circle weeding substantially increased basal diameter and branching when compared to no weeding, in situations with labour constraints, it can be used to lessen the deleterious effects of weeds. This revised version was published online in June 2006 with corrections to the Cover Date.