Relationship between shrub cover and available forage in Mediterranean shrublands

Shrublands with kermes oak (Quercus coccifera L.) as a dominant species play an important role in the nutrition of grazing animals in the Mediterranean region during all seasons of the year. Their proper management, however, is inhibited by the lack of easy and inexpensive methods for measuring available forage. In this paper, the spatial distribution of available forage as well as its relationship with shrub cover measured on the ground and in aerial photographs were investigated. The research was conducted in kermes oak shrublands of central Macedonia, Greece. Two-phase sampling was applied by using 1:15,000 aerial photographs to select 47 plots, 0.1 ha each, on an area of 545 ha where shrub cover and available forage (herbage, current year's and total browse) were measured. These measurements were carried out on four shrub cover classes: open (0 to 15%), moderate (16 to 40%), dense (41 to 70%) and very dense (71 to 100%); and three height classes: low (0 to 0.5 m), middle (0.6 to 1.0 m) and tall (1.1 to 1.5 m). High resolution aerial photographs (1:6,000) taken during the year of ground sampling were used to estimate shrub cover and correlate to ground measurement. Estimated cover had a high correlation (r 0.96) with ground measurements in open, moderate and dense shrub stands. The open to dense cover classes had significantly more available forage than the very dense cover class; and the low height class significantly higher than the other two classes. The regression of available forage with shrub cover measured on the ground and on aerial photographs produced non-linear equations with high coefficients of determination (R² > 0.70) only when shrub height up to 0.5 m irrespective of the cover class was considered. It is concluded that shrub cover measured on aerial photographs can be used to predict shrub cover on the ground as well as available forage in kermes oak shrublands provided that the shrubs are not too tall (up to 0.50 m).This revised version was published online in November 2005 with corrections to the Cover Date.     

Forage value of Mediterranean deciduous woody fodder species and its implication to management of silvo-pastoral systems for goats

Forage value of 10 deciduous woody fodder species during six stages of maturity as well as their acceptance by goats in July and August were studied in Macedonia, northern Greece. The fodder species studies wereAmorpha fruticosa L.,Carpinus orientalis Mill.,Colutea arborescens L.,Corylus avellana L.,Fraxinus ornus L.,Ostrya carpinifolia Scop.,Pyrus amygdaliformis Vill.,Quercus pubescens Willd.,Quercus sessiliflora Salich, andRobinia pseudoacacia L. with two accessions, common and spineless. All these species are integral components of the mediterranean silvo-pastoral systems. Monthly forage samples were collected throughout their growing period (May to November), which coincides with the long dry summer when herbaceous plants are dormant, and analyzed for crude protein content, neutral detergent fiber (NDF), lignin and in vitro organic matter digestibility (IVOMD). Comparing the leguminous species (Robinia pseudoacacia, Amorpha fruticosa, Colutea arborescens) with the remaining species, the leguminous one had on average a higher (P0.05) content of crude protein (21.1%, 21.0% and 17.1% vs. 10.5–13.3%, respectively) and higher (P0.05) IVOMD values (58.4%, 56.0% and 60.0% vs. 47.3–52.8, respectively). Moreover, the leguminous species were among species with lower NDF (42.3%, 45.0% and 35.2% vs. 36.0–48.9%, respectively) and lignin content (7.1%, 8.3% and 9.1% vs. 7.6–10.9%). All species showed a significant increase in crude protein when new leaves appeared (May). Most of the fodder species had digestibilities in the higher range (>55% IVOMD) and low NDF content (<53.5%) during the growing season (first five stages). Lignin contents ranged from 5.9% (A. fruticosa, May) to 16.0% (O. carpinifolia, Nov.).Robinia pseudoacacia had the highest relative acceptance index whileAmorpha fruticosa, Colutea arborescens andCorylus avellana the lowest. It is concluded that deciduous woody fodder species may play a significant role as sources of nutrients in the mediterranean silvo-pastoral systems during the summer period of seasonal nutritional shortage.     

Forage production of woody fodder species and herbaceous vegetation in a silvopastoral system in northern Greece

Introduction of woody plants in silvopastoral systems could be an appropriate land-use for the poor sandy soils of the Mediterranean semiarid zone. Forage production of four woody fodder species and herbaceous vegetation in relation to plant spacing and animal (sheep) grazing was studied in a silvopastoral system on such a site in Macedonia, northern Greece. The woody fodder species tested were Robinia pseudoacacia L., Gleditsia triacanthos L., Amorpha fruticosa L. and Morus alba L. They were planted at the spacings 1.5 × 1.5 m,2.5 × 2.5 m and 3.5 × 3.5 m and kept in a shrubby form by topping. They were grazed by sheep (stocking rate of 1.1 sheep/ha/year) in early July and late August of 1992, 1993 and 1994. Among the species Robinia yielded the highest forage production (394 kg/ha). The spacing 1.5 × 1.5 m had the highest (P ≥ 0.05) forage production per area unit (280 kg/ha) while the spacing 3.5 × 3.5 m had the highest forage production per plant (91.8 g/plant). No competition was observed between the woody and the herbaceous plants in the various spacings probably due to topping of the woody species every winter. Percent utilisation of the native herbage dropped as forage of the woody species increased. This revised version was published online in June 2006 with corrections to the Cover Date.     

Voluntary intake by sheep and goats ofGliricidia sepium fed in three states and at three levels of supplementation to a basal diet ofPanicum maximum

Crude protein content andin sacco dry matter (DM) loss after 72 h of incubation in West African dwarf (WAD) sheep and goats of fresh, wilted and dried leaves ofGliricidia sepium were compared. Additionally, voluntary DM intakes by WAD sheep and goats ofG. sepium leaves presented in the fresh, wilted and dried states at 10, 20 and 30% levels of supplementation were investigated in two separate experiments. The crude protein content and DM loss from dried leaves were relatively lower than fresh and wilted leaves. At all levels of supplementation, the voluntary DM intakes of fresh and wilted leaves by WAD sheep and goats were relatively higher than dried leaves. The results suggest thatG. sepium leaves should be fed either in the fresh or wilted states to WAD sheep and goats, at levels between 20 and 30% of the total daily DM allowance.     

Rumen degradation in sheep,goats and cattle and voluntary intake by sheep of four browse species

Two experiments were conducted using dried leaves ofAlchornea cordifolia, Ficus capensis, Manniophytum fulvum andAlbizza niopoides. In Experiment 1, dry matter (DM) degradation characteristics were investigated using thein sacco nylon bag technique in West African Dwarf (WAD) sheep, WAD goats and Bunaji steers. In Experiment 2, voluntary intake of the browse forage when fed as supplements to sheep at 0, 10 and 30% levels was measured. In Experiment 1,A. cordifolia andM. fulvum had significantly higher rapidly degradable DM fraction thanA. niopoides andF. capensis. Averaged across browse species, the extent of DM degradation for sheep (58.3%) was significantly higher than for goat (47.7%) or cattle (44.1%). Ranking order of browse species for the extent of DM degradation was:F. capensis>A. cordifolia=M. fulvum=A. niopoides. In Experiment 2, as the level of supplementation increased from 10 to 30%, voluntary intake ofA. niopoides andM. fulvum increased while voluntary intake ofA. cordifolia andF. capensis declined. The results suggest that dried leaves ofA. niopoides andM. fulvum are more acceptable to WAD sheep than those ofA. cordifolia andF. capensis.     

Pine needle consumption and bark stripping by sheep grazing annual pastures in young stands of widely spaced Pinus radiata and P. pinaster

The consumption of the pine needles and the stripping of bark by sheep grazing annual pastures in three open stands of P. radiata and one of P. pinaster were measured. The P. radiata were four years old and the densities were 250, 500 and 750 trees ha^-1. The P. pinaster included two, three and four year-old trees and the density was 440 trees ha^–1.Needles were eaten immediately after the sheep were admitted and this continued throughout the year. Within ten weeks of the start of winter grazing, sheep stocked at 7–10 ha^–1 had eaten about half of the accessible needles on both species where densities were less than500 trees ha^–1. The estimated consumption was about 260 g sheep^–1 day^–1 for the P. radiata. Bark stripping then commenced and continued throughout spring and summer on most plots. In some plots at low tree density, bark was stripped from more than 35% of the trees. In denser stands, needle consumption per tree was less and bark was stripped from less than 5% of the trees.Bark damage was most common on the smaller trees, and severity of stripping was negatively correlated with tree size. Of all the trees with bark damage, 22% of the P. pinaster and 14% of the P. radiata had more than half of the stem circumference stripped. A number of these will probably suffer both stem distortion and growth retardation, and some may die.Methods of reducing the incidence of bark damage are discussed.     

Seed production in Polylepis australis (Rosaceae) as influenced by tree size, livestock and interannual climate variations in the mountains of central Argentina

The expansion of tree species within a grassland-woodland matrix relies heavily on an abundant seed crop, which may be affected by many factors; among these, browsing by livestock has gone largely ignored. Here we explore how seed production is affected by tree size, grazing by large domestic herbivores and interannual climate fluctuations in a small-sized tree (Polylepis australis, Rosaceae), which dominates the remnant forests in the high mountains of central Argentina. Seed number and seed mass per tree were quantified in 100 different-sized trees located in areas with and without livestock. Using seed traps we also determined seed rain variation in 15 plots between 2005 and 2008. The estimated number of seeds per tree ranged from 0 to 224,000 and increased with tree height (power relation); for trees smaller than 354 cm in height, seed production was lower in areas with livestock and higher in areas without livestock. Mass per seed increased with tree height, with no significant livestock effect. The largest seed rain was recorded in 2008, probably due to growth of seed trees and not in response to climate. To promote seed production and forest expansion, livestock should be excluded from areas with small trees, such as forest edges.     

Mycorrhizal dependency and growth responses of Acacia nilotica and Albizzia lebbeck to inoculation by indigenous AM fungi as influenced by available soil P levels in a semi-arid Alfisol wasteland

A series of available phosphorus (Olsen) levels ranging from 10 to 40 ppm were achieved in a semi-arid soil. The influence of the levels of phosphorus on the symbiotic interaction between two subtropical tree species, Acacia nilotica and Albizzia lebbeck, and a mixed inoculum of indigenous arbuscular mycorrhizal (AM) fungi was evaluated in a greenhouse study. The extent to which the plant species depended on AM fungi for dry matter production decreased as the levels of soil P increased, but the degree of this decrease differed in the two species tested. Acacia nilotica colonized by AM fungi showed a significant increase in shoot P and dry matter at a soil P level of 10 ppm whereas in Albizzia lebbeck, such increase occurred at 20 ppm. Mycorrhizal inoculation response disappeared beyond soil P levels of 25 ppm in Acacia nilotica and 30 ppm in Albizzia lebbeck. Levels of soil P greater than 25 ppm suppressed AM fungus colonization in both species. Soil P levels of 30 and 40 ppm and 40 ppm caused negative mycorrhizal dependencies (MD) in Acacia nilotica and Albizzia lebbeck respectively. Values of MD for both species were negatively correlated with soil P levels. Based on the MD values, regression equations were developed to predict MD for given levels of available P.     

Heartwood/sapwood variation of western redcedar as influenced by cultural treatments and position in tree

We studied heartwood and sapwood variation in western redcedar (Thuja plicata) at three sites, including a 95-year-old naturally regenerated, unmanaged stand, a 35-year-old planted spacing trial, and a 30-year-old naturally regenerated stand to which thinning and fertilization treatments had been applied. In the 95-year-old stand, we studied within-tree variation in heartwood and sapwood. In the thinning/fertilization trial and the planted spacing trial, we studied effects of cultural practices and growth rate on heartwood and sapwood. In the trees that we studied, sapwood width was generally fairly narrow, rarely exceeding 3.5 cm. Heartwood formation in western redcedar appeared to begin at a relatively small stem diameter (7 cm) and at a young age, probably 10–15 years. The amount and proportion of heartwood increased with distance downward from the top of the tree, with the implication that older trees will contain a greater proportion of heartwood than younger trees. For any given age, it appears that cultural treatments that favor rapid growth will result in stems with greater amounts of both sapwood and heartwood, and a greater proportion of heartwood.     

Growth and nitrogen status of young walnuts as affected by intercropped legumes in a Mediterranean climate

Walnut trees (Juglans nigra L. and Juglans nigra × regia NG23) were intercropped with alfalfa (Medicago sativa L.) or sainfoin (Onobrychis sativa L.) forage legumes compared to a grass (Festuca arundinacea Schr., fescue), or to spontaneous weeds as a control in two Mediterranean sites (Castries and Notre-Dame de Londres) near Montpellier (France). Tree growth, soil water depletion and nitrogen content of the tree leaves were monitored to assess the impact of both water competition and possible facilitation resulting from fixed nitrogen transfer from the leguminous crops to the trees. At Castries, where alfalfa and fescue were compared, they were found to have the same impact on tree growth. At Notre-Dame de Londres where sainfoin was compared with a spontaneous grassing treatment, the sainfoin crop was more competitive to the walnuts. The nitrogen content of walnut leaves was enhanced when intercropped with nitrogen fixing species at both sites. Perennial leguminous intercrops were more competitive for soil water resources than fescue or weeds, but in the long term this may be compensated by the improved nitrogen status of the trees. This compensating effect was observed during a rather rainy year. The overall impact of leguminous intercrops on tree growth may depend on the frequency of dry (competitive) and wet (non-competitive) years. This revised version was published online in June 2006 with corrections to the Cover Date.     

The role of herbicide in savanna restoration: Effects of shrub reduction treatments on the understory and overstory of a longleaf pine flatwoods

Woody plant encroachment is a threat to savanna ecosystems worldwide. By exploiting differences in the physiology and seasonality of herbaceous species and encroaching hardwoods, herbicides can be used to control woody shrubs in savannas without causing lasting harm to desirable vegetation. We applied three herbicides and one tank mix to control shrubs following removal of the slash pine (Pinus elliottii Engelm.) canopy and replanting with container-grown longleaf pine (Pinus palustris Mill.) seedlings in a mesic-wet savanna in the southeastern USA. The herbicides tested were imazapyr, sulfometuron methyl, hexazinone, and a hexazinone + sulfometuron methyl tank mix. 4 years after application, no negative effects on understory species richness, diversity, evenness, or community composition were evident in any of the herbicide treatments. Oaks (Quercus spp.), one of the dominant shrub genera on the study site, were resistant to sulfometuron methyl, and this herbicide was therefore ineffective both as a pine release treatment and for enhancing herbaceous species cover. Imazapyr was the most effective treatment overall, leading to significant improvements in longleaf pine seedling growth and also enhancing herbaceous species cover. Both hexazinone and the hexazinone + sulfometuron methyl tank mix provided some seedling growth and understory enhancement as well. In particular, the tank mix significantly increased wiregrass cover relative to the control. Shrubs resprouted quickly following a dormant-season prescribed fire in the fifth year after treatment, indicating that herbicide-related increases in herbaceous cover may be lost if an aggressive prescribed fire program is not implemented.     

Growth and herbage productivity of Gliricidia in Panicum maximum pasture as influenced by seedbed preparation,planting and weed control techniques

Interplanting Gliricidia (Gliricidia sepium [Jacq.] Walp.) into poor quality native grass can improve the quality of pasture. But information on methods to establish the tree legume into existing pasture is scarce. This study was designed to compare the effects of disc-ploughing, hoeing, or rotary tillage operations, and direct seeding or planting out potted seedlings on growth and dry matter yields of Gliricidia in grass pasture. The Guinea grass (Panicum maximum) pasture was first mowed to a height of 10 cm. Then the seedbed was prepared by either hoeing 0.5 m strip or rototilling 0.5 m strip with a 2-wheel tractor or disc-ploughing 1.0 m strip with a 4-wheel tractor. Eight weeks old potted seedlings were planted or seeds were sown direct. At 6 months after planting (MAP), trees in disc-ploughed strips averaged 81 cm in height, about 35% taller than trees in hoed- or rotary-tilled strips. Potted seedlings (average height 77 cm) grew 37% taller than direct-seeded trees. At 12 MAP trees in disc-ploughed strips yielded 95% more leaf DM (1170 vs. 600 kg/ha) than trees in hoed- or rotary-tilled strips. In order to intercrop Gliricidia into existing Guinea grass pasture, it is necessary to plant potted seedlings previously raised in nursery into 1.0 m wide strips disc-ploughed with 4-wheel tractor. Weed control is necessary.     

Regional variation in rate of mass loss of Pinus sylvestris needle litter in Swedish pine forests as influenced by climate and litter quality

The climatic influence on plant litter decomposition has been successfully correlated on a regional level by using estimated actual evapotranspiration (AET) and annual mass loss. This approach was applied to decomposition studies carried out in a transect along Sweden with litter incubated in four different forest types. A unified needle litter was used and among 14 Scots pine sites about 80% of the mass‐loss rate could be explained. A simple model was made on the influence of both climate and nutrient concentrations (nitrogen and phosphorus) on mass‐loss rate. About 90% of the first‐year mass loss could be explained by this approach. As early decomposition stages were studied (<40%) no influence of lignin was observed.     

孟加拉涝原地区村林居住的宗教社团偏爱的乔木和灌木树种及使用的造林材料研究

2002年1月至6月对孟加拉涝原地区两个不同的宗教部落(印度教和穆斯林教)的传统家园森林进行了探索性研究，包括印度教和穆斯林教社团对树种(乔木和灌木)的偏爱度、类似性、造林材料及来源、植树地点和间距。研究发现Mangifera indica作为乔木树种，Ocimum sanctum作为灌木树种为印度教社团最喜爱的树种；Artocarpus heterophyllus和Lawsonia inermis分别为穆斯林社团最喜爱乔木树种和灌木树种。两中不同宗教社团选择乔木数种的相同性为86．57％，灌木树种为78．48％。两个宗教部落使用种子和苗木作为造林材料最多。乔木树种的造林材料主要来自家园(39％)灌木树种主要来自自然界(40％)。表3参27。     

Monitoring the effects of land use and cover changes on net primary production: A case study in China's Yongding River basin

Changing land uses and cover types influence vegetation composition and health, so understanding the effects of these changes on net primary production (NPP) provides an important tool for monitoring ecosystem responses to environmental change. Using remote-sensing images and precipitation, temperature, and total solar radiation data from 1978, 1987, 2000, and 2005, and a light utilization efficiency model, we studied the effects of changes in these parameters and land use and cover types on NPP in China's Yongding River basin. We determined the NDVI of vegetation in the basin, and used these results to estimate the NPP of vegetation in the basin and the influence of land use and cover type changes on NPP under two climate scenarios: one in which the precipitation and temperature of the previous period remain unchanged into the following period, that is, use the climate in 1978, 1987 and 2000 to analyze NPP data in 1987, 2000 and 2005 respectively, and another in which both parameters remain constant at their 1978 values throughout the study period. With the climate unchanged from the former period, NPP in 1987 decreased compared with the 1978 value by 20–50 gC/m², and then increased by more than 40 gC/m² in western and central parts of the basin from 1987 to 2000. From 2000 to 2005, NPP decreased in the northwestern, northern, and eastern parts of the basin. With climate unchanged from 1978 to 2005, NPP increased from 1987 to 2000 by from 10 to 30 gC/m² in most areas. From 2000 to 2005, some farmland in western and northwestern parts of the basin and some forest land were converted into grassland, decreasing NPP by 40–50 gC/m².     

Opportunity for hybridization between two oak species in mixed stands as monitored by the timing and intensity of pollen production

The opportunity of cross-pollination in mixed stands of two oak species (cork oak and holm oak) was studied by characterizing individual phenologies of flowering. In the spring of 1998 at one stand consisting of 64 marked trees, there was a period of 19 days when maximal pollen release in one species and stigma receptivity in the other occurred simultaneously, enabling interspecific gene flow in either direction. This happened in spite of an average time separation of 22 days between the two species, reflecting a considerable intraspecific variation in the timings of flowering. Flowering intensities (as estimated from male flower abundance) were high, but fruiting intensities were comparatively low. Shortly after pollination, considerable abortion of female flowers and early fruits was recorded. In 2000, the interspecific overlap of phenologies was drastically reduced due to a delay in cork oak flowering. On the other hand, the individual timings were repeatable for most trees, at least in holm oak. Two other mixed stands were subject of parallel studies, with similar results in all traits except for a less dramatic reduction in fruiting intensities. In spite of the high opportunity for cross-pollination in 1998, and given the lack of hybrids among the progenies from the subsequent fruiting season [Oliveira, P., Custódio, A.C., Branco, C., Reforço, I., Rodrigues, F., Varela, M.C., Meierrose, C., 2003. Hybrids between cork oak and holm oak: isoenzyme analysis. Forest Genet. 10, 283–298], it can be concluded that the prerequisite of cross-pollination is clearly insufficient for hybridization to succeed. Post-pollination processes must play an important role in the maintenance of reproductive isolation between the two species.     

Tree planting by small producers in the tropics: A comparative study of Brazil and Panama

Forest regrowth is a notable phenomenon across the tropical forest latitudes. Such reforestation takes place in the wake of land abandonment, occurs cyclically in a rotational agricultural system, and may result from the deliberate planting of trees by farmers. Although less extensive than successional forest regeneration, tree planting by small farmers can have potentially important environmental impacts at both the site and global scale. This paper examines tree-planting efforts by small farmers in the tropical frontier regions of Panama and Brazil in order to gauge the magnitude of reforestation activities, and to identify factors that influence these efforts. This paper discusses the environmental regulations, forestry law, and tenure institutions in both countries, and performs a comparative analysis of reforestation efforts with information derived from household surveys (n = 356) and in-depth tree planting interviews (n = 35). Results from logistic regression are also presented. Our results show that tree planting occurs more frequently in Panama, which we attribute to greater external support in the provisioning of extension and materials and strong market incentives. We suggest that the proximity of the study sites to Panama City facilitates external support and market drivers. Finally, our results suggest that land tenure security is an influential determinant of reforestation activities in both countries.This revised version was published online in November 2005 with corrections to the Cover Date.     

油茶芽苗砧嫁接育苗成本及生产效益分析——以韶关小坑林场2015年育苗生产为例

通过在韶关国营小坑林场良种基地应用油茶芽苗砧嫁接育苗技术培育苗木,分析其成本效益,为广东地区油茶良种苗木繁育技术推广提供参考,也为广大育苗经营户提供生产、投资的依据。     

冰雪致湖南森林毁损原因、损失评估及重建设想

2008年1-3月,采取现场观测、查阅林班档案、标准地调查、影像分析等方法对2008年1月冰灾后湖南主要受害地区森林进行较全面的综合调查.结果如下:桉树、湿地松、楠竹等大面积人工林毁损;部分地区马尾松、杉木、阔叶树天然次生林机械折损量大;多种绿化大苗、柑桔等经济林树种商品价值丧失殆尽;多数树种因树冠冰晶负荷过重导致机械损伤,桉树、柑桔等少数树种既具机械损伤,又兼有明显的生理损害.冰灾的基本原因是拉尼娜现象而致的气候异常,直接原因是有利于冰晶形成的气象因子组合.过量汽车尾气、工厂烟尘、烹饪等产生的烟气等污染物形成的纳米级微颗粒(1～10 nm)悬浮质,促进了雾和霾的形成.适度低温与饱和湿度的配合及长时间稳定维持,造成了树枝等支撵物上冰晶过度发育.提出灾后重建、减灾补损的具体措施.     

Application of salicylic acid induces antioxidant defense responses in the phloem of Picea abies and inhibits colonization by Ips typographus

The adaptive plasticity of Norway spruce (Picea abies) against attack by Ips typographus depends on systemic acquired resistance which involves salicylic acid (SA), and an antioxidant system both recognized as valuable stress markers in ecophysiological studies. In the presented field experiment, 100 mM SA was applied to the bark sections of Norway spruce prior to being attacked by bark beetles, in order to study interactions with antioxidants and its significance for mediating stress-tolerance under natural conditions. SA-treatments significantly elevated the total SA levels over the whole sampling period. Total glutathione (tGSH) and total cysteine (tCys) increased by 167% and 80%, respectively, two weeks after treatment, in comparison with controls. In contrast, SA-treatment caused an initial deterioration in total ascorbic acid (tASC) and enhanced the percentage of dehydroascorbic acid (DHA), but activated tASC levels over later sampling dates. The initial bark beetle attack was characterized by a significant decline in total SA levels, which was accompanied by a transient degradation and oxidation of their ascorbate-glutathione system. This initial reaction was significantly alleviated by SA-application and characterized by 175% higher tGSH contents, when compared to moderately-affected untreated trees. One month after pheromone dispensers were placed on trees, an intensification of ascorbate-glutathione system occurred within moderately-affected bark, but to a greater extent after SA-treatment. Total SA levels within SA-treated moderately-affected trees remained at the control level until June. In contrast, strong attack was characterized by a successive increase in total SA up to 252% following SA-treatment in June, whereas a 110% increase of SA was determined within severely affected control-bark. A strong attack was further characterized by a degradation of tGSH and total phenolics (tPH), a moderate increase in tASC and an oxidation of the ascorbate-glutathione pool within untreated bark. In the SA-treated trees the redox state was unaffected by severe colonization and the degradation of antioxidants was significantly alleviated. In addition, SA-treated bark had significantly less entrance holes and exhibited fewer and shorter maternal galleries than control-bark. From this perspective, exogenous SA was successfully implicated as an activator of systemic acquired resistance in Norway spruce, providing tolerance against the complex interactive effects of bark beetle attack and environmental factors.