Caribaea Var Research Articles

Evaluation of tropical forage legumes under Pinus caribaea var hondurensis in Turrialba, Costa Rica

A number of tropical forage legume species were sown in Turrialba., Costa Rica, in plots in the open and under an even cover of Pinus caribaea var hondurensis of basal area 30m2/ha. Mean light level under the trees was 18% full sunlight. After 19 months, species showing good shade tolerance and adaptation to local conditions were: Centrosema spp., Desmodium spp., Flemingia congesta, Galactia striata. Species of poor performance in the shade were: Stylosanthes spp., Indigofera hirsuta, Cajanus cajan, Stilozobium sp.. Canavalia ensiformis, an annual, grew well in the shade, as did Lablab purpureus and Vigna unguiculata. It is suggested that further work be done on the shade tolerant species for eventual use as components of silvopastoral systems. Recommendations are made concerning germplasm collections, evaluation methodology and research for silvopasture development.

The Potential of Pine Hybrids in South Africa

SYNOPSIS The performance of a variety of pine hybrids in trials in Zululand and the Transvaal is described. Results are compared with earlier assessments of some Zululand trials. The potential of pine hybrids, especially those of Pinus elliottii and P. caribaea var. hondurensis, for commercial planting in the subtropical regions of South Africa is discussed. Pine hybrids, especially of P. elliottii and P caribaea var. hondurensis, appear to be particularly suitable for large scale use in Zululand, with the possibility of increasing timber production by at least 50 %.

Tolerance ofPinus caribaeavar.hondurensistransplants to eleven herbicides

Summary Eleven herbicides were tested for their toxicity to newly planted Pinus caribaea var. hondurensis seedlings. Haloxyfop-methyl, sethoxydim, oxyfluorfen, tridiphane, fenoxaprop-ethyl, and clopyralid at half, once and twice the rates recommended for effective weed control were not toxic to P. caribaea either as pre- or post-plant treatments. Post-plant applications of terbumeton/terbuthylazine, chlorsulfuron, and triclopyr significantly reduced height growth and survival. Terbumeton/terbuthylazine and chlorsulfuron also significantly reduced height and survival when applied prior to planting. Simazine, resolved isomer formulation of fluazifop-butyl, and simazine/fluazifop- butyl mixture were not toxic to P. caribaea as post-plant applications, but pre-plant treatments with these herbicides injured the transplants. It is thought that this injury was caused by the mixing of herbicide-treated topsoil into the root zone of the transplants during outplanting.

Field performance of Pinus caribaea var. Hondurensis seedlings with specific ectomycorrhizae and fertilizer after three years on a savanna site in Liberia

Seedlings of Pinus caribaea var. hondurensis were grown in containers for 4 months in a bush nursery in Gbarnga, Liberia. Vegetative inocula of Pisolithus tinctorius (Pt), Thelephora terrestris (Tt), and soil inoculum, called Monrovia mixture (MM), collected from under 16-year-old trees of the same species, were used to form specific ectomycorrhizae on the seedlings. Seedlings in these three treatments received the same fertility in the nursery as seedlings in a noninoculated control treatment; in a fifth nursery treatment noninoculated control seedlings received 25% more fertilizer. Seedlings inoculated with Pt, Tt, and MM had ectomycorrhizae on 61, 18, and 6% of their short roots, respectively. These inoculated seedlings were significantly smaller, with lower top/root ratios, and contained less foliar N than seedlings in either control treatment. A trace of ectomycorrhizae was detected microscopically on seedlings in both control treatments. It was concluded that this contamination came from the introduced Tt which formed abundant fruit bodies in the nursery. Seedlings were outplanted on a prepared savanna site near Gbarnga; half of the seedlings in each treatment were fertilized. Seedlings were measured at the end of each 7.5-month rainy season and each 4.5-month dry season for 3 years. At the end of the first rainy season, seedlings inoculated with Tt in the nursery and the two controls had an average of 49% Tt ectomycorrhizae, regardless of field fertilization. Over 2000 Tt fruit bodies were found during each rainy season in each of these plots. Seedlings in the Pt and MM treatments had 82 and 86% ectomycorrhizae, of which only 2–11% were formed by Tt. The fungi were reisolated from their respective ectomycorrhizae. Rhizosphere soil from seedlings with Pt ectomycorrhizae contained more total N than soil from seedlings in other treatments. These samples, however, did not differ in N 2-fixation rate (acetylene reduction technique) from other soil samples containing less total N collected at the beginning of the third dry season. After the first rainy season, seedlings with Pt ectomycorrhizae with and without field fertilization had significantly more N and other elements in needles than most other treatments. These differences were much less after the third rainy season. After 3 years, seedling survival (96.0-83.6%) was not seriously affected by treatment. Seedlings with Pt ectomycorrhizae in fertilized plots had significantly greater seedling and plot volumes than those in other treatments. Only seedlings with Pt ectomycorrhizae responded to field fertilization. Seedlings with MM ectomycorrhizae had greater volumes than seedlings with Tt ectomycorrhizae or seedlings in either control treatment. Seedlings intentionally inoculated with Tt were not significantly different in any field measurement from those in the two control treatments contaminated with Tt. Seedlings with Pt and MM ectomycorrhizae grew as much or more during the short dry season than seedlings of other treatments grew during the longer rainy season. Physical properties of stem tissue sampled at the end of the third rainy season did not vary by treatment. Bark averaged 35.5% of stem tissue. Moisture content of wood was 192.5% and specific gravity of wood and bark was 0.293. Fruit bodies of Alpova pachyphloeus were found in 4- and 5-year old pine plantations and those of Thelephora sp. were found on pine seedlings left in the nursery prior to fungal introductions. Since all of these seedlings had been inoculated with MM in the Gbarnga nursery, these fungi coild be components of the MM inoculum or they could be indigenous on native trees in the Gbarnga area. Pt fruit bodies were observed 2 km downwind from the study site in young plantations of Eucalyptus grandis and E. camaldulensis. Apparently basidiospores of Pt were windblown from the study site to these plantations. It was concluded that differences in seedling growth caused by specific ectomycorrhizal and field fertilization treatments were attributed to differences in amounts of ectomycorrhizae formed during the growing season and in efficacy of specific ectomycorrhizae in nutrient and water absorption.

Impact on soils of plantations of Pinus caribaea stands in natural tropical savannas

Soil properties to a depth of 90 cm under stands of 14-year-old Pinus caribaea var. hondurensis and adjacent natural savanna forest cover were compared in the savanna zone of Nigeria. No significant differences in soil physical characteristics were noted except modest increases in top soil bulk density values under the pine. But soil chemical properties, viz. organic carbon, total N, extractable P and exchangeable K, Ca and Mg showed statistically significant decline in the upper 10 cm of the mineral soil as a result of reafforestation with P. caribaea. Soil changes in relation to planation age were also discussed.

Effect of restricted watering and its combination with root pruning on root growth capacity, water status and food reserves ofPinus caribaea var.hondurensis seedlings

Six-month old Pinus caribaea var. hondurensis seedling were subjected to various regimes of restricted watering and their combinations with root pruning to determine a suitable technique of producing seedlings with optimum physiological condition for successful bare—root planting.

Título en español

Araucaria heterophylla fue la especie más prometedora de las seis especies siempre verdes examinadas para conveniencia como árbol de Navidad. Pinus caribaea var. hondurensis podría ser utilizable también. Callitris intratropica, Casuarina equisetifolia y Cryptomeria japonica crece bien pero poseen una apariencia pobre. Pinus echinata murió.

The growth response of Pinus caribaea mor. var. hondurensis bar and golf seedlings to fertilizer application on the Serdang soil series

A 3 3 × 2 factorial, soil bioassay experiment was conducted to study the effect of nitrogen, phosphorus, potassium and magnesium on the growth of Pinus caribaea var. hondurensis seedlings on the Serdang soil series. Nitrogen was applied at levels equivalent to 0 and 112 kg/ha; phosphorus and potassium, 0, 336.2 and 560.4 kg/ha and magnesium, 0, 67.2 and 112 kg/ha. The study was carried out over a period of 6 months. The height of the seedlings was measured at regular intervals of 2 weeks. At the end of the experimental period, the collar diameter, shoot, root and total plant weights were determined. The study showed that phosphorus was the most important single nutrient required by P. caribaea on this soil type. P and PK effects contributed significantly to height growth. The 336.2 kg/ha level of P was more effective than the 560.4 kg/ha level. N, P and NP promoted radial growth, while for dry matter production, only N and P were important. For radial growth and dry matter production, the 560.4 kg/ha level of P was more effective. Potassium and magnesium, either alone or together, inhibited growth, especially that of the shoot, but this effect was not prominent when phosphorus was also added.

Foxtailing of Pinus caribaea var. Hondurensis in Fiji: Frequency, distribution of occurrence and wood properties

Frequency of foxtailing in five stands of Pinus caribaea aged between 3 and 9 years was found to vary between 7 and 20%. Heights of foxtails were greater than normals on average at all ages, whereas diameters were greater only at 3 and 5 years. Foxtail stems were more often straighter and had fewer malformations than normals. Basic density from pith to cambium of foxtails and normals differed by only 3.1 kg/m 3, an insignificant amount.

The response ofPinus caribaea mor. var. Hondurensis seedlings to nitrogen, phosphorous and potassium fertilizers

A soil pot culture experiment was conducted to study the response ofPinus caribaea var. hondurensis seedlings to the N, P, K fertilizers in a 33 factorial combination of nutrients in four replicates. For this purpose, seedlings were grown in plastic pots in soils collected from Bahau pine experimental area. These soils belong to Durian series and are generally poor in nutrients.

Some Observations on the Quality of the Timber of South African Grown Pinus caribaea var. caribaea and var. hondurensts / WAARNEMINGS OP DIE KWALITEIT VAN DIE HOUT VAN SUID-AFRI-KAANSGEKWEEKTE PINUS CARIBAEA VAR. CARIBAEA EN VAR. HONDURENSIS

ABSTRACT The timber of 24 to 26 year old Pinus caribaea var. caribaea and var. hondurensis trees grown in South Africa is studied especially in regard to resin infiltration, low density, and yields of structural and box timber grades. The results are compared with data for P. elliottii and are discussed in regard to earlier investigations conducted on the timber in South Africa and on the species grown in young Queensland plantations.

A study on the suitability of some soils in Northern Surinam for Pinus caribaea var. Hondurensis.

The soils developed on the Coesewijne deposits and belonging to the entisol, spodosol and oxisol orders, were grouped into five sub-divided classes according to their suitability. Characteristics used to determine suitability were influence of ground-water, texture, organic matter distribution and distribution of biopores. (Abstract retrieved from CAB Abstracts by CABI’s permission)

The productivity and nitrogen economy of artificial ecosystems comprising various comninations of perennial legumes and coniferous tree species

The effect of the perennial legumes Lotononis bainesii, Desmodium uncinatum, and Phaseolus atropurpureus on the growth of the indigenous conifers Araucaria cunninghamii and Agathis robusta and the exotic pines Pinus elliottii var. elliottii, P. taeda, and P. caribaea var. hondurensis was tested over a 5 year period on a lateritic podzolic soil. The legumes grew vigorously but under the dense canopy of the exotic pines began to decline in the third season. They depressed the yield of the exotic pines but stimulated that of the native conifers. They greatly increased the nitrogen content of the standing crop (vegetation plus litter) of native conifers, but had little or no effect on the nitrogen content of exotic pines. No change in soil nitrogen status was detected below a depth of 4 in., but the amount of total nitrogen in the 0-4 in. horizon was increased by Phaseolus and Desmodium, as was the nitrogen content of the whole soil-plant system. These increases occurred mainly in association with the native conifers, since the exotic pines shaded the legumes and reduced their effectiveness. The marked stimulation of the native conifers by the leguminous cover crops confirms previous findings that nitrogen is the primary limiting nutrient for these trees on lateritic podzolic soils in the coastal lowlands of southern Queensland. Exotic pines did not benefit from the presence of legumes, yet produced dry matter yields of 5-6 tons/acre/year. There is evidence of substantial accretion of nitrogen, amounting to 20-45 lb/acre/year, to ecosystems dominated by Pinus spp., even in the absence of legumes; most of this extra nitrogen was contained in the trees.