Many interspecific hybrids have been produced among Leucaena species, some with great potential for high-value wood and forage production. Superior hybrids are often highly sterile, and vegetative propagation would be essential for their exploitation. Four experiments were conducted to investigate factors affecting the rooting of cuttings of Leucaena hybrids. Nine hybrids were studied that represented different ploidy levels (2x, 3x, and 4x), different levels of seedlessness, different ages (5–16 years) and varying leaflet sizes. Rooting ability basically depended on genotype, with only a few hybrids failing to root. Cuttings required leaflets to root, and half or more of a leaf led to higher frequencies of better roots. One-node cuttings had the same rooting ability as two-node cuttings. Rooting ability decreased dramatically in the cooler, low-light winter seasons of lowland Hawaii. Etiolation treatments increased rooting ability significantly for two difficult-to-root hybrids.

The traditional Acacia senegal bush-fallow in North Kordofan, Sudan, was disrupted and the traditional rotational fallow cultivation cycle has been shortened or completely abandoned, causing decline in soil fertility and crop and gum yields. An agroforestry system may give reasonable crop and gum yields, and be more appealing to farmers. We studied the effect of tree density (266 or 433 trees ha⁻¹) on two traditional crops; sorghum (Sorghum bicolor) early maturing variety and karkadeh (Hibiscus sabdariffa), with regard to physiological interactions, yields and soil water depletion. There was little evidence of complementarity of resource sharing between trees and crops, since both trees and field crops competed for soil water from the same depth. Intercropping significantly affected the soil water status, photosynthesis and stomatal conductance in trees and crops. Gum production per unit area increased when sorghum was intercropped with trees in low or high density. However, karkadeh reduced the gum yield significantly at high tree density. Yields of sorghum and karkadeh planted within trees of high density diminished by 44 and 55% compared to sole crops, respectively. Intercropping increased the rain use efficiency significantly compared to trees and field crops grown solely. Karkadeh appears to be more appropriate for intercropping with A. senegal than sorghum and particularly recommendable in combination with low tree density. Modification of tree density can be used as a management tool to mitigate competitive interaction in the intercropping system.

Swidden cultivation is the traditional agricultural system in most parts of the Amazonian rain forest. In a remote area in the Manu National Park, Peru, this system was analysed in two indigenous Matsiguenka communities. Diversity of cultivated plants on fields and in homegardens are presented in the current study. Cultivated plants were noted on two to four plots per field on 46 fields, making a total of 126 survey plots. Nineteen homegardens were studied as well. Dominating species cultivated on fields is cassava (Manihot esculenta). Fruit trees such as the peach palm (Bactris gasipaes), guava (Psidium guajava) or Inga edulis, but also cotton (Gossypium barbadense) and a medicinal plant (Cyperus sp.) predominate in more than 75 % of the homegardens analysed. Species diversity increases steadily from 18 and 24 species on 1- and 2-year-old fields to 26, 29 and 66 species in young, medium old and old homegardens, respectively. Seventy-one different species in total were found in all homegardens analysed and 25 in swidden fields. Diversity of species cultivated in homegardens is low compared to other studies in the rain forest of the Amazon. This seems to be due to their remoteness from the next urban centre and to the fact that they are native communities with still low external exchange of information. These findings are in contrast to the hypothesis that remoteness from urban centres increases species richness because subsistence production is based on a broad variety of species. In contrast to species richness in homegardens, differences in species richness in swidden fields between the present and other studies could not be found.

Information is lacking on the potential of leguminous fodder trees such as Leucaena leucocephala as a feed resource to supplement the native forages in traditional grazing management systems in the tropics. Two studies were conducted (1) to assess traditional fodder banks’ forage nutritive potential on animal production, and (2) to investigate the effect of Leucaena leucocephala leaf meal (LLM) supplementation on growth of steers grazing standing hay basal forages in the dry season. The traditional forages had low nutritive values indicated by low mean crude protein (CP) of 23 g kg⁻¹ dry matter (DM), and high fibre contents of 717, 546 and 153 g kg⁻¹ DM for neutral detergent fibre (NDF), acid detergent fibre (ADF) and acid detergent lignin (ADL), respectively. The forages were poorly degraded in sacco and had low metabolisable energy (ME) (4.2–4.6 MJ kg⁻¹ DM). Mean washing losses A, slowly degradable DM fraction, B, potential degradability, (A+B) and mean 48 h DM degradability (DMD) of grazing land forages were 70, 471, 541 and 326 g kg⁻¹ DM, respectively. In the supplementation study, 16 growing steers (160.8±0.24 kg) were randomly allocated into four groups, in a completely randomized design. Four LLM treatment diets (T1, T2, T3 and T4), with four levels: 0, 0.4, 0.6 and 0.8 kg DM for control, low, medium and high LLM levels, respectively, were randomly allocated to the animals in the four groups for 70 days (d). LLM supplementation (p<0.05) improved mean weight gain from −0.30 to 0.26 kg steer⁻¹ d⁻¹, for T1 and T4, respectively. Steers on T4 gained (p<0.05) more weight compared to the animals in T1 and T2, though there was no (p>0.05) difference in weight gains between animals on T3 and T4 (0.14 vs. 0.26 kg steer⁻¹ d⁻¹, respectively). Standing hay basal forages alone could not sustain animal productivity during dry seasons unless corrected for protein. Higher levels of LLM supplementation prevented weight losses and improved the performance of grazing steers, a management practice thought appropriate to low income pastoralists in semiarid western Tanzania.

The relationships between trees and understory crops are very important in agroforestry systems. Also, above ground interactions can be related to canopy structure. However, measurements of canopy structural parameters, either destructive or indirect, are time-consuming or prohibitively expensive. The present work explored the use of digital photography as a simple method to characterise the extent of canopy closure (CC), defined as the area of tree canopies projected onto the horizontal ground surface beneath, and expressed as a percentage of the ground covered. Measurements were made in two Eucalyptus (Eucalyptus nitens, Deane and Maiden) plantations and a subtropical mixed legume woodland dominated by Albizia (Albizia sp), Kidneywood (Eysenhardtia sp.) and Desert Fern (Lysiloma sp.). Images were captured at dawn to minimise light scattering and the number of sunlit foliage elements. Mean CC estimates provided by analysis of images obtained using digital cameras with contrasting performance, a Kodak DC-120 and a Canon EOS D1, were similar in precision and accuracy both between the two cameras and to those provided by a Li-Cor LAI-2000 canopy analyser. Bias between the estimates provided by the Kodak and Canon cameras was –0.02, between the Kodak and LAI-2000 was –0.07 and between the Canon and LAI-2000 was –0.05. Data from a pruning experiment using alder also demonstrated the repeatability of estimates obtained with a photographic method using the Kodak camera. The number of ring sensors within the LAI-2000 used to estimate CC affected agreement between the photographic method and the LAI-2000.

Small farms in Appalachia are economically challenged due to complex topography and soil constraints that limit productivity. Most farms have considerable acreage in forest, some of which is on the least productive sites, which contributes little income. The purpose of this study was to determine management and microclimate impacts on the establishment of an agro-forest for increasing the economic value of the forested land resource. A 1.2 ha forest clear-cut was planted with red oak (Quercus rubra) as the desired mature forest species alternated with rows of Chinese chestnut (Castanea mollissima), pawpaw (Asimina triloba), hazelnut (Corylus americana), and white pine (Pinus strobus) for generating income as the forest matures. Oak and chestnut required protection from deer. Oak had the lowest survival rate (61%) and chestnut had the highest survival rate (94%). While providing protection, Tubex plastic tubes also resulted in spindly tree growth. Plastic tubes did, however, improve pawpaw survival. Oak did best on well-drained locations. Chestnut and hazelnut were negatively impacted by forest edge more than oak or pawpaw. Overall there was a high degree of variability in tree growth suggesting that on low productivity sites, a planting density substantially higher than the desired final stand may be warranted to optimize the tree-vigor/micro-site match.

The importance of agroforestry systems in temperate regions in providing habitat for small mammals has not been investigated. Numbers and densities of small mammals were assessed by live trapping in a complex farming landscape including mature hedgerows, arable fields, areas of trees planted at forestry density (2,500 trees ha–1) and trees in an agroforestry configuration (178 trees ha⁻¹) consisting of rows of trees separated by arable alleys. Over a 2 $${1\over 2}$$ -year period, 1680 animals were captured; 69% were Apodemus sylvaticus L., 20% Sorex araneus L. and 10% Clethrionomys glareolus Schreber. Small numbers of Mus domesticus Rutty, Sorex minutus L., and Neomys fodiens Pennant were also caught. The density of captures of A. sylvaticus and S. araneus varied little over the whole farming landscape in contrast to C. glareolus which had a greater density of captures in mature hedgerows. However, for the small mammals collectively, away from hedgerows, the highest density of captures was found in the agroforestry tree rows (15.5 per 100 trap nights) and the least in open arable crop (4.3), with both arable alleys and forestry density trees having intermediate values (9.1 and 9.2 respectively).Densities of captures of A. sylvaticus were greater in the tree rows and arable alleys than in the forestry area and the adjacent open arable crop, whereas for S. araneus they were greater in the habitats with trees. It is clear that the range of habitats in an agroforestry system is valuable for small mammal conservation.

Arid and semi-arid lands are becoming increasingly important for food and fiber production worldwide. Windbreak and shelterbelts can improve the productivity of such lands, but their establishment can be difficult and/or expensive. This study examined the survival and growth of Arizona cypress (Cupressus arizonica) propagated in four different container sizes, then outplanted at three planting sites in either fall 1994 or spring 1995. Trees were planted in plots prepared with three treatments (v-ditch and weed barrier, singly and in combination), along with an undisturbed control. Generally, more intensive site preparation and larger stock size was associated with greater survival. While some such stock size and treatment combinations showed high mortality at 28 days, subsequent mortality through six growing seasons was relatively low. Stock size and site preparation did not strongly impact height after six growing seasons.

Agroforestry systems based on poplar (Populus deltoides) are becoming popular in eastern and northern parts of India. Therefore studies on the structure and function of the systems are important. The investigations included allometric equations for above- and belowground tree components, crop and plantation floor biomass and litter fall estimation at Pusa, Bihar, India. Biomass, floor litter mass, litter fall and net primary productivity (NPP) of plantations increased with an increase in age of trees whereas, crop biomass for any specific crop interplanted with poplar decreased with the age of the plantation. The total plantation biomass increased from 12.08 to 90.59 Mg ha⁻¹ and NPP varied from 5.69 to 27.9 Mg ha⁻¹ year⁻¹. The biomass accumulation ratio ranged from 2.1 to 3.2. Total annual litter fall was in between 1.95 and 10.00 Mg ha⁻¹ year⁻¹, of which 92–94% was contributed by leaf litter. Compartmental models were developed for dry matter distribution in agroforestry systems involving young (3-year-old) and mature (9-year-old) poplar trees interplanted with various crops, the crops being grown in two rotations maize (Zea mays) – wheat (Triticum aestivum) – turmeric (Curcuma domestica) and pigeonpea (Cajanus cajan) – turmeric. This study substantiates the potential of Populus deltoides G₃ under agroforestry combinations.