Lower Tree Height Research Articles

Nutrient Accumulation and Flower Bud Formation Affected by the Time of Terminal Bud Set on Water Sprouts of Persimmon

Heavy pruning to lower tree height of persimmon results in excessive production of water sprouts and reduced yield. This experiment was conducted on ‘Fuyu’ (Diospyros kaki) trees to assess if the time for terminal bud set of water sprouts affected flower bud formation. Some sprouts were not pruned to serve as fruiting branches for the next season. Thirty to 40 water sprouts were tagged in 2005 and 2006, the growth of which stopped from mid-June to late August. The later terminal buds set, the lower the percent dry weight in the apical 10 cm. The apical segments of sprouts that continued to grow to mid- to late August were characterized by low soluble sugars, starch, and inorganic elements such as nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), and magnesium (Mg) compared with those that set terminal buds earlier. The number of flower buds from the water sprouts that set terminal buds by early August the previous year bore more than 12 flower buds the next year, whereas those that grew to mid- to late August bore fewer than three. It was concluded that water sprouts could be used as fruiting branches for the next year as long as terminal buds set by early August, thereby alleviating yield reductions that come with heavy pruning.

Influence of Soil Applied Paclobutrazol on Tree Growth andCanopy Spread in Acid Lime (Citrus aurantifolia Swingle)

A field experiment was conducted at Horticultural College and Research Institute, Periyakulam during 2006-2007 and 2007-2008 to study the effect of paclobutrazol (Cultar) on tree growth and canopy spread in five year old trees of acid lime. The trees were treated with paclobutrazol at different concentrations viz., 1.25, 2.50, 3.75 and 5.00 g a.i per tree following randomized block design. The results were recorded during on and off seasons of the year. Application of paclobutrazol (PP333 ) had significant effect on tree height in both the seasons. Soil application of paclobutrazol 2.50 g had the highest tree height in the main (3.33 and 3.18 m) and off season (3.86 and 3.48 m) during the year 2007-08 and 2006-07 respectively. The lowest tree height (3.05 and 3.21 m) was registered under paclobutrazol 3.75g during the main and off seasons of the year 2006-07 and 2007-08. Tree spread between east to west was found to be wide (4.40 and 4. 58 m) in soil application of paclobutrazol at 3.75 g during main and off seasons of the year 2006-07 and 2007-08. Similarly, tree spread between north to south, soil application of paclobutrazol at 3.75 g recorded wide tree spread (4.62 and 4.88 m) in the main and off season of the year 2006-07 and 2007-08.

Summer pruning effect on tree growth and fruit production of persimmon

This paper reviews the effect of summer pruning in persimmon (Diospyros kaki Thunb.) with regard to its positive and negative aspects on tree growth and fruit production. In order for this practice to be of a significant value, a clear understanding is needed to appreciate the fact that so many variables are involved and much remains to be substantiated. Major reasons for summer pruning of persimmon are to improve fruit quality by enhancing light penetration into the tree canopy and to restrict vegetative shoot growth. Summer pruning generally suppresses tree growth even though it elevates leaf activity. Positive effects of summer pruning on skin color, soluble solids, and appearance of fruits are observed mainly in those orchards where the trees are heavily dormant-pruned to lower tree height and to secure space in high density plantings. Secondary shoot pruning and topping could also improve fruit quality, increasing flower bud formation of remaining shoots. Summer-pruning effects are highly dependent on its severity and timing to affect tree growth, shoot regrowth, reserve accumulation, and fruit quality.

Occurrence, proportion, and vertical distribution of red heartwood in paper birch

Normal paper birch ( Betula papyrifera Marsh.) wood has a clear and uniform color. However, some paper birch trees contain reddish-brown-, discolored wood known as red heartwood. Its occurrence, proportion, and vertical distribution were investigated. One hundred and fifty trees were randomly sampled from three stands located at the Montmorency Forest, 75 km north of Quebec City, Quebec, Canada. A subsample of 18 trees showing occurrence of red heartwood at stump height were felled, and 5 cm thick disks were cut at every 0.5 m of height. Red heartwood volume, proportion, and vertical distribution were determined from the disks. Trees with larger diameter at breast height and lower tree height had a higher probability of red heartwood occurrence. Red heartwood starts occurring in 40-year-old trees on average in the stands studied. The volume of red heartwood was positively correlated with tree age, and the proportion of red heartwood was positively related to tree age, and negatively related to the amount of sunlight on the live crown. Red heartwood proportion was 13.3% of the tree merchantable volume, mostly located under the live crown.

Simulated glacial and interglacial vegetation across Africa: implications for species phylogenies and trans‐African migration of plants and animals

AbstractThe paleoenvironmental context of plant and animal species evolution (including glacial migrations and population separations) is based on a very patchy and incomplete paleo‐phytogeographic record. It was our objective, therefore, to provide an additional source for paleovegetation comparison by presenting simulations from a state‐of‐the‐art fully coupled earth system model (HadCM3LC). We simulated potential paleovegetation distributions following pre‐Industrial and last glacial maximum (LGM) climate forcing for the continent of Africa. Our LGM simulations indicate that tropical broadleaf forest was not severely displaced by expanding grasslands within central Africa, although the outer extent of closed forest decreases, particularly in the north. Our simulations indicate that the structure of glacial forests may have been much different from today, in that LGM simulations indicate that forests were likely characterized by lower leaf area indexes, lower tree heights and lower vegetation carbon content. On the other hand, warmer interglacial climate (like our pre‐Industrial climate scenario) results in simulated expansion of tropical forest from coast to coast across central Africa that we postulate could have acted as a barrier to plant and animal species migrations. We suggest that our modeling experiments have implications for the interpretation of phylogenetic data, including that of our own species, Homo sapiens sapiens.

Comparison of pest detection in two persimmon cultivation methods

To elucidate the requirements for fruit planting systems with efficient pest detection, we compared the efficiency of two persimmon cultivation methods, a table-shaped method and a typical standing-tree method, using round labels as detection targets. The results showed that a low tree height and branch movements are required for efficient pest detection. Experiments, in which workers wore goggles to simulate an elderly person's narrower field of view, showed that the table-shaped method was more efficient for detection because branches were within a frame and were easy to scan. This cultivation method proved to useful under the circumstances tested in this study, i.e., advanced age of growers in Japan.

Contrasting net primary productivity and carbon distribution between neighboring stands of Quercus robur and Pinus sylvestris

Standing biomass, net primary production (NPP) and soil carbon (C) pools were studied in a 67-year-old pedunculate oak (Quercus robur L.) stand and a neighboring 74-year- old Scots pine (Pinus sylvestris L.) stand in the Belgian Campine region. Despite a 14% lower tree density and a lower tree height in the oak stand, standing biomass was slightly higher than in the pine stand (177 and 169 Mg ha(-1) in oaks and pines, respectively), indicating that individual oak trees contained more biomass than pine trees of similar diameter. Moreover, NPP in the oak stand was more than double that in the pine stand (17.7 and 8.1 Mg ha(-1) year(-1), respectively). Several observations indicated that soil organic matter accumulated at higher rates under pines than under oaks. We therefore hypothesized that the pines were exhibiting an age-related decline in productivity due to nutrient limitation. The poor decomposability of pine litter resulted in the observed accumulation of organic matter. The subsequent immobilization of nutrients in the organic matter, combined with the already nutrient-poor soil conditions, resulted in a decrease in total NPP over time, as well as in a substantial shift in the allocation of NPP toward fine roots. In the oak stand, litter is less recalcitrant to decay and soil acidity is less severe; hence, organic matter does not accumulate and nutrients are recycled. This probably explains why NPP was much higher in the oaks than in the pines and why only a small proportion of NPP was allocated to oak fine roots.

Manual and Chemical Inducement of Sylleptic Shoots in Apple in the Fruit-tree Nursery

The ability of various treatments to induce sylleptic shoot development of nursery trees of the apple `Jonagold' and `Golden Delicious' on root-stock M.9 was investigated. The leader management techniques were: removal of sub-terminal leaves, removal of sub-terminal leaves with application of 0.25% Paturyl 10 WSC (6-benzyladenine), and treatment with 0.25% Paturyl 10 WSC (two times at 24 days interval); application of 20% Promalin (GA4+7) two times in 9 days interval; and control; starting when scion length was 75 cm. Removal of sub-terminal leaves increased total branch length, but not stimulated the lateral branching. Treatments with Paturyl resulted in the lower tree height, in the higher number of branches, and in the greater branch length. Removal of sub-terminal leaves in combination with Paturyl increased the lateral shoot number even more than treatment only with Paturyl. Promalin increased branching, but had little influence on the total branch length. In addition, Promalin decreased branch crotch angles.

Small mammal microhabitat use on young loblolly pine regeneration areas

Loblolly pine ( Pinus taeda L.) regeneration or establishment impacts a large area over the southern US but few studies have examined the microhabitat relationship of small mammals on young pine stands. We collected over 1600 small mammals on natural and artificial loblolly pine regeneration areas. Twenty-five habitat variables describing cover, forage, and structure were measured or derived at each trap station. We used discriminant function analysis (DFA) to construct microhabitat utilization models for the six most abundant small mammal species common to young loblolly pine regeneration areas including the southern short-tailed shrew ( Blarina carolinensis), golden mouse ( Ochrotomys nuttalli), white-footed mouse ( Peromyscus leucopus), cotton mouse ( P. gossypinus), harvest mouse ( Reithrodontomys humulis), and cotton rat ( Sigmodon hispidus). We compared vegetation characteristics at stations where each species was captured versus stations where it was not captured. Models of species microhabitat associations helped explain observed differences in species succession and abundance. Coarse woody debris (i.e. logs and stumps) was found to be an important microhabitat component for O. nuttalli. Logs and stumps were important to P. gossypinus, P. leucopus and S. hispidus. Shrew capture stations had a significantly taller canopy and significantly greater biomass of vines than did non-shrew captures sites. Golden mouse capture stations had significantly longer logs, shorter distance to nearest log, and lower herbaceous profile diversity. Distance to nearest tree was significantly greater while tree height and vine cover were significantly lower at white-footed mouse capture stations. Cotton mouse microhabitat variables describing woody biomass were greater and stump size, tree height and distance to logs were significantly lower at capture stations. Harvest mice capture stations were characterized as having significantly lower tree height than non-capture stations. Cotton rat microhabitat was characterized by twelve variables but cotton rats were collected almost exclusively on the youngest stands with the greatest grass and herbaceous structure. Numerous variables play an important role in determining habitat quality for the array of small mammal species commonly found in early successional pine habitats in the southeast. Microhabitat models help to explain some of the patterns of species occurrence and succession. While the methods used in this study do not necessarily demonstrate preferred habitat, our results allow identification of areas of use.

Niche segregation among three sympatric species of squirrels inhabiting a lowland dipterocarp forest, Peninsular Malaysia

Niche segregation among three sympatric species of squirrels, Callosciurus notatus, C. caniceps and Sundasciurus lowii inhabiting a lowland dipterocarp forest was studied in the Ulu Gombak Forest Reserve, Selangor Darul Ehsan, Malaysia. Diurnal activity of the three species had two peaks. Sundasciurus lowii and C. caniceps were more restricted in vertical space, concentrated mainly at lower tree heights, whereas C. notatus was slightly less restricted. Sundasciurus lowii were more selective in their diet: bark was the main food item. The two Callosciurus spp. took a variety of food items, although fruit was the major component. The niche breadth values in diurnal activity patterns, vertical space uses, and food preferences revealed that C. notatus was a generalist compared with the other two species. Differences in selection of tree species rather than food item may be the main factors that determine niche occupancy for the three species of squirrels in the study area.

Habitat use by Pileated Woodpeckers at two spatial scales in eastern Canada

To study the multiple spatial scale pattern of habitat use by Pileated Woodpeckers (Dryocopus pileatus L.), we compared the vegetation characteristics at used sites with those at unused sites at macrohabitat (154 ha radius plots) and microhabitat (ca. 0.04 ha radius plots) scales in the La Mauricie region of Québec. Used macrohabitats were those in which woodpeckers were detected at playback stations. Used microhabitats corresponded to sites showing signs of foraging (i.e., excavated cavities). Pileated Woodpeckers responded to vegetation structure at both scales sampled. Macrohabitats used by woodpeckers had relatively low percentages of mixed shade-intolerant hardwood stands, coniferous stands, and stands of relatively low stem density and tree height, but included high percentages of 51- to 90-year-old stands. Microhabitats used by woodpeckers were characterized most strongly by a high density of large snags but also by a high density of small-diameter snags and a low density of shade-intolerant hardwood trees and coniferous trees [Formula: see text]30 cm diameter at breast height. The concordance between the observed and predicted use of micro- and macro-habitat plots was independent of spatial scale (logistic regression, χ20.05,1 = 1.8, P = 0.18, n = 429), suggesting that habitats use by woodpeckers was influenced to a similar extent by habitat features measured at both spatial scales. Because Pileated Woodpeckers are likely to require specific habitat features at different spatial scales, forest-management guidelines intended to conserve this umbrella species should consider a multiple spatial scales approach.

Distribution of breeding songbirds in Bradfield Woods, Suffolk, in relation to vegetation and coppice management

Distribution and abundance of breeding birds were examined in 62 ha of ancient, actively coppiced, woodland in relation to vegetation and age of the coppice. The composition of bird communities in coppice of 3–8 years of growth was distinctly different to that in other ages of coppice. Most warblers, Nightingale and Dunnock strongly selected coppice 11 years). Most of these distribution patterns were best explained by variations in the density of the shrub layer or by a combination of relatively low tree height yet high canopy cover. At the scale of the entire wood there was little evidence that tree species composition affected bird distribution. However, within young (3–8 years) and within old (10–30 years) coppice there was evidence of tree species effects. It is argued that subtle patterns in ...

Timing of Longleaf Pine Seedling Release from Overtopping Hardwoods: A Look 30 Years Later

Abstract Significant differences in longleaf pine (Pinus palustris) growth among early and delayed seedling release treatments were recorded at age 10, but these differences had disappeared upon reexamination at age 31. A study begun in 1949 included six release treatments: complete seedling release from overtopping hardwoods at ages 1, 2, 3, 4, and 8 years, plus an unreleased check. Treatments were randomly applied among six 0.1-acre plots in each of six blocks, which included both poor and average sites. Seedling development was observed through age 10. When pines in five surviving blocks (two poor site, three average site) were remeasured in 1979 at age 31, there were no significant differences among release treatments in average tree heights and diameters or stand basal areas and volumes. The check treatment had significantly lower tree heights, stand densities, and stand volumes than any release treatment.