M. P. González-Hernández

Nutritional attributes of understory plants known as components of deer diets.

Nutritive quality of vegetation is important when evaluating the habitat to sustain wildlife. Crude protein, fiber content and in vitro digestibility were evaluated for 17 shrubs, 7 trees, 2 ferns, 3 forbs, and 4 grasses species of Galician (NW Spain) woodlands understory. Nutritional attributes showed forbs, Frangula alnus Miller, Hedera helix L. and Linocera periclymenum L. as plants with the highest forage value. Crude protein levels of Rubus sp., Robinia pseudacacia L., Castanea sativa Miller, and grasses could meet deer nitrogen requirements but their low IVOMD and high fiber percentages make them mid-low feed value forages. Understory layer of oakwoods provides higher quality forage than conifer or eucalyptus stands. Crude protein and digestibility of plants peaked in spring-summer and the highest fiber content occurred in winter. Seasonal fluctuations in forage quality makes seasonal management and seasonal plans necessary.

Production patterns of understory layers in several Galician (NW Spain) woodlands: Seasonality, net productivity and renewal rates

Production and quantity, as well as the renewal rates of understory vegetation biomass, were measured in shrublands and oak, conifer, and eucalyptus forest stands. A significant (P<0.05) negative correlation was found between understory biomass and tree canopy cover. However, stand tree density and basal area were not significantly correlated with understory. Herbs were the major contributors to seasonal fluctuation in production. Although productivity differed among stands, the seasonal pattern of production did not. Production was higher in the warmer seasons for all sites. This higher productivity was correlated with plant species richness. The renewal rates of the understory biomass were dependent on the herbaceous/woody plant ratio. Different responses were found in productivity of shrubs, forbs, ferns, and grasses after cutting understory biomass. These dissimilarities were also conditioned to forest type.

Research observation: Hydrolyzable and condensed tannins in plants of northwest Spain forests

Tannins are secondary metabolites that may influence feeding by mammals on plants. We analyzed hydrolyzable and condensed tannins in 30 plant species consumed by livestock and deer, as a preliminary attempt to study their possible implications on browsing and grazing in forest ecosystems. Heathers (Ericaceae) and plants of the Rose (Rosaceae) family had tannins, while forbs, grasses and shrubs other than the heathers did not show astringency properties. We found the highest tannin content of all the species in Rubus sp., with the highest value around 180 mg TAE/g dry weight in spring. Potentilla erecta, Alnus glutinosa and Quercus robur were next with 57 to 44 mg TAE/g dw. Total tannins in heathers ranged from 22 to 36 mg TAE/g dw. Levels of condensed tannins were higher than hydrolyzable for most of the species. Only Betula alba, Calluna vulgaris, Pteridium aquilinum and Vaccinium myrtillus had 100% hydrolyzable tannins. Tannin content of the species changed seasonally with highest values during the growing season, corresponding to late winter or early spring, depending on the species.

Research observation: Hydrolyzable and condensed tannins in plants of the northwest

Tannins are secondary metabolites that may influence feeding by mammals on plants. We analyzed hydrolyzable and condensed tannins in 30 plant species consumed by livestock and deer, as a preliminary attempt to study their possible implications on browsing and grazing in forest ecosystems. Heathers (Ericaceae) and plants of the Rose (Rosaceae) family had tannins, while forbs, grasses and shrubs other than the heathers did not show astringency properties. We found the highest tannin content of all the species in Rubus sp., with the highest value around 180 mg TAE/g dry weight in spring. Potentilla erecta, Alnus glutinosa and Quercus robur were next with 57 to 44 mg TAE/g dw. Total tannins in heathers ranged from 22 to 36 mg TAE/g dw. Levels of condensed tannins were higher than hydrolyzable for most of the species. Only Betula alba, Calluna vulgaris, Pteridium aquilinum and Vaccinium myrtillus had 100% hydrolyzable tannins. Tannin content of the species changed seasonally with highest values during the growing season, corresponding to late winter or early spring, depending on the species. DOI:10.2458/azu_jrm_v56i5_gonzalez-hernandez

Seasonal variation in concentrations of fiber, crude protein, and phenolic compounds in leaves of red alder (Alnus rubra): nutritional implications for cervids.

We sought to determine whether changes in chemical composition could be a factor in increased utilization of red alder (Alnus rubra) by the two cervids, the Columbian black-tailed deer (Odocoileus hemionus columbianus) and Roosevelt elk (Cervus elaphus roosevelti), during the fall in parts of the Douglas fir region of the Pacific Northwest. We found that concentrations and astringency of phenolic compounds decreased from spring through fall, while crude protein content remained high. We conclude that red alder leaves provide a significant source of digestible protein for cervids during fall, when availability of nutrients in most forage species is generally declining.

Effect of Plant Sterols and Tannins on Phytophthora ramorum Growth and Sporulation

Elicitin-mediated acquisition of plant sterols is required for growth and sporulation of Phytophthora spp. This study examined the interactions between elicitins, sterols, and tannins. Ground leaf tissue, sterols, and tannin-enriched extracts were obtained from three different plant species (California bay laurel, California black oak, and Oregon white oak) in order to evaluate the effect of differing sterol/tannin contents on Phytophthora ramorum growth. For all three species, high levels of foliage inhibited P. ramorum growth and sporulation, with a steeper concentration dependence for the two oak samples. Phytophthora ramorum growth and sporulation were inhibited by either phytosterols or tannin-enriched extracts. High levels of sterols diminished elicitin gene expression in P. ramorum; whereas the tannin-enriched extract decreased the amount of ‘functional’ or ELISA-detectable elicitin, but not gene expression. Across all treatment combinations, P. ramorum growth and sporulation correlated strongly with the amount of ELISA-detectable elicitin (R2 = 0.791 and 0.961, respectively).

Horse grazing systems: understory biomass and plant biodiversity of a Pinus radiata stand

Horse grazing systems may affect productivity and biodiversity of understory developed under Pinus radiata D. Don silvopastoral systems, while acting as a tool to reduce the risk of fire. This study compared continuous and rotational grazing systems effect upon biomass, fractions of stem, sprouts, leaves and woody parts of Ulex europaeus L. and alpha (Species Richness, Shannon-Wiener) and beta (Jaccard and Magurran) biodiversity for a period of four years in a P. radiata silvopastoral system. The experiment consisted of a randomized block design of two treatments (continuous and rotational grazing). Biomass, and species abundances were measured - biodiversity metrics were calculated based on these results for a two years of grazing and two years of post-grazing periods. Both continuous and rotational grazing systems were useful tools for reducing biomass and, therefore, fire risk. The rotational grazing system caused damage to the U. europaeus shrub, limiting its recovery once grazing was stopped. However, the more intensive grazing of U. europaeus plants under rotational had a positive effect on both alpha and beta biodiversity indexes due to the low capacity of food selection in the whole plot rather than continuous grazing systems. Biomass was not affected by the grazing system; however the rotational grazing system is more appropriate to reduce U. europaeus biomass and therefore forest fire risk at a long term and to enhance pasture biodiversity than the continuous grazing system.

Tannins as nutritional constraints for elk and deer of the coastal Pacific Northwest.

In the coastal Pacific Northwest, diets of elk (Cervus elaphus roosevelti) and deer (Odocoileus hemionus columbianus) are dominated by shrubs, ferns, and forbs solution17,18 or agarose gel.19 In this paper, we refer to the capacity to precipitate proteins as astringency.20

Composition of the heartwood essential oil of incense cedar (Calocedrus decurrens Torr.)

No abstract available

Agroforestry in the European common agricultural policy

Agroforestry is a sustainable land management system that should be more strongly promoted in Europe to ensure adequate ecosystem service provision in the old continent (Decision 529/2013) through the common agricultural policy (CAP). The promotion of the woody component in Europe can be appreciated in different sections of the CAP linked to Pillar I (direct payments and Greening) and Pillar II (rural development programs). However, agroforestry is not recognised as such in the CAP, with the exception of the Measure 8.2 of Pillar II. The lack of recognition of agroforestry practices within the different sections of the CAP reduces the impact of CAP activities by overlooking the optimum combinations that would maximise the productivity of land where agroforestry could be promoted, considering both the spatial and temporal scales.