High-value Trees Research Articles

Economic evaluation of ecosystem goods and services under different landscape management scenarios

Human-induced changes in the natural environment are affecting the provision of ecosystem goods and services (EGS). Land use plans rarely include the value of public ecosystem services such as climate regulation and biodiversity due to difficulties in valuing these services. In this study, we assessed total economic value for five important ecosystem goods and services under five future land-use scenarios using varying levels of costs, prices and discount rates. Results indicated that at higher discount rates normally applied to commercial activities, and assuming the current prices for goods and services, net present value (NPV) was highest for landscape management scenarios aimed at maximising agricultural production. Potential income from services such as carbon and biodiversity does not offset projected income lost from agriculture due to land-use changes. At higher discount rates, NPV was negative for the two scenarios aimed at enhancing the longer term ecological sustainability of the landscape. These results indicate that income from carbon sequestration and biodiversity conservation would need to be considerably higher than current levels in order to justify focusing management of this landscape on ecological outcomes. At lower discount rates (at levels normally associated with public investments), the more ecologically appropriate ‘mosaic farming system’ had the highest NPV, indicating that this type of system might be attractive for investors interested in longer term return horizons or wider public benefits. Higher income from carbon or biodiversity, or increased return from timber by using high value tree species, could potentially make more ecologically appropriate systems profitable at higher discount rates.

Biology of the bark beetleIps grandicollis Eichhoff (Coleoptera:Scolytinae) and its arthropod, nematode and microbial associates: a review of management opportunities forAustralia

AbstractThe five‐spined bark beetle,Ips grandicollis, is an exotic pest inAustralia that preferentially attacks stressed pine trees, includingPinus radiataD. Don, but it can also attack healthy trees. The beetle has been present inAustralia for 70 years, feeding principally on logging debris, with occasional outbreaks resulting in damage to plantations. Attack on trees stressed by drought, fire or storm damage leads to occasional significant losses. In recent years,I. grandicollishas been observed to attack ‘trap trees’ treated with herbicide to make them attractive toSirex noctilioFabricius as part of a successful biological control programme against this wood wasp.Ips grandicollisis able to tolerate a wide range of climatic conditions, and has an extensive geographical range (limited by host tree plantings). The economic impact ofI. grandicollisis exacerbated by adults vectoring a fungus,Ophiostoma ips(Rumbold) Nannfeldt, which discolours the outer sapwood and contributes to tree death. Nematodes also are also associated withI. grandicollis, both in the body cavity and under the elytra. The dominant nematode isContortylenchus grandicolliMassey, which is found internally, in haemocoel, the gut and the head region of the majority of adult beetles. Mites and bacteria are also associated withI. grandicollisbut their biology is not well known. Since the first detection ofI. grandicollisinAustralia, various bio‐control and other management strategies have been tested. While a better understanding of the microbial and nematode associates ofI. grandicollismay yield novel approaches for the management of this exotic pest, semiochemical‐based disruptants offer more immediate scope, particularly for protecting small areas of high value trees such as trap tree plots.

Emerald Ash Borer Invasion of North America: History, Biology, Ecology, Impacts, and Management

Since its accidental introduction from Asia, emerald ash borer (EAB), Agrilus planipennis Fairmaire (Coleoptera: Buprestidae), has killed millions of ash trees in North America. As it continues to spread, it could functionally extirpate ash with devastating economic and ecological impacts. Little was known about EAB when it was first discovered in North America in 2002, but substantial advances in understanding of EAB biology, ecology, and management have occurred since. Ash species indigenous to China are generally resistant to EAB and may eventually provide resistance genes for introgression into North American species. EAB is characterized by stratified dispersal resulting from natural and human-assisted spread, and substantial effort has been devoted to the development of survey methods. Early eradication efforts were abandoned largely because of the difficulty of detecting and delineating infestations. Current management is focused on biological control, insecticide protection of high-value trees, and integrated efforts to slow ash mortality.

Field Note: Emamectin Benzoate Reduces Defoliation by <I>Choristoneura occidentalis</I> Freeman (Lepidoptera: Tortricidae) on Three Host Species

Stem injections of insecticides are generally regarded as a safer and a more environmentally friendly option (compared to foliar sprays) for protecting high-value trees against insects in sensitive areas or near homes. We carried out a three year study to determine the efficacy of trunk injections of emamectin benzoate for protection of foliage of three common host species attacked by the western spruce budworm, Choristoneura occidentalis Freeman (Lepidoptera: Tortricidae). Defoliation by C. occidentalis was significantly reduced by nearly half over a 3-year period on treated compared to control grand fir, Douglas-fir, and alpine fir. Reduction of defoliation was comparable to standards used for aerial spraying (e.g., 50%) of conifer feeding budworms in Canada.

Modelling individual and collective species responses to climate change within Small Island States

Very little empirical work has been done to assess the potential impacts of climate change upon terrestrial biodiversity within small islands, many of which contribute to global species diversity due to high levels of endemicity. This study illustrates projections of not only individual but also the ‘collective’ response of a group of high conservation value tree species to climate change within the Caribbean small island of Trinidad. The species distribution modelling algorithm MaxEnt was used to construct models of the realised present environmental space occupied by these species based on present day climate and other environmental factors. These models were then used to estimate present and future (2050; SRES A2) distributions of these species across Trinidad. Both present and future model output were incorporated to create change maps which illustrate projected expansions, contractions and areas of stable environmental space for each species. Individual change maps were combined to create a ‘collective’ change map portraying projected changes in the environmental space of this species group as a whole. Most individual species and the collective group response were projected to lose more than 50% of present environmental space, with the latter being limited to the southern edge of the island. Our results suggest that small islands may experience an eventual disappearance of endemics and other valuable species under SRES A2 conditions, which may serve to further depreciate global terrestrial species diversity. Application of this ‘collective’ response may be particularly useful for planning within the limited geographic spaces available for conservation within small islands.

Using weaver ants Oecophylla smaragdina to control two important pests on African mahogany Khaya senegalensis in the Northern Territory of Australia

African mahogany, Khaya senegalensis, is a high-value timber tree species. Pilot plantings showed that the species performed well in the wet–dry tropical areas of northern Australia, but the yellow looper, Gymnoscelis sp., and the bush cricket, Myara yabmanna, caused severe damage to the trees. The weaver ant, Oecophylla smaragdina, is an effective bio-control agent of a range of insect pests in tropical tree crops and forest trees. To determine whether the ants control these mahogany pests, field experiments were conducted from April 2006 to January 2009 at two sites near Darwin, Australia. The fraction of the total number of trees damaged per year was 4.2–32.4% by yellow loopers and 0–10.4% by bush crickets on trees with weaver ants, but 25–70.4% by yellow loopers and 25–100% by bush crickets on trees without the ants. The damaged trees with weaver ants were attacked on fewer occasions than damaged trees without the ants. Significantly fewer trees with weaver ants were damaged per monitoring occasion (2.1–8.4% at Berrimah Farm and 0.5% at Howard Springs by yellow loopers; 0–2.2% by bush crickets) than trees without the ants (24.2–51.3% at Berrimah Farm and 5.0% at Howard Springs by yellow loopers; 18.1–40.7% by bush crickets). Data suggested that weaver ants were effective bio-control agents of the two pests.

Symposium 9: Rocky Mountain Futures: Preserving, Utilizing, and Sustaining Rocky Mountain Ecosystems

Symposium 9: Rocky Mountain Futures: Preserving, Utilizing, and Sustaining Rocky Mountain Ecosystems

Treatment Strategies Using Imidacloprid in Hemlock Woolly Adelgid (Adelges tsugae Annand) Infested Eastern Hemlock (Tsuga canadensis Carrière) Trees

Due to the widespread establishment of hemlock woolly adelgid (Adelges tsugae Annand) (HWA) across the range of eastern hemlock (Tsuga canadensis Carriere), woodland trees may be infested for many years before treatment is made. Symptoms of prolonged infestation include extensive dieback and thinned canopies. Imidacloprid, a systemic neonicotinoid insecticide, is a useful and effective tool to manage HWA. In this study, mature, large diameter trees in poor condition were treated with imidacloprid. Trees were treated once by trunk and/or soil injection in Asheville, North Carolina, U.S. Following application, changes in tree growth, HWA density and imidacloprid residues were measured for three years. Trees treated with imidacloprid recovered, whereas the untreated trees continued to struggle. Trees injected with imidacloprid accumulated compound in the canopy, facilitating refoliation and the imidacloprid persisted for three years. This extended activity of trunk-injected imidacloprid was attributed in part to slow upward movement through the restrictive tracheid vascular system and to perennial needle retention. The imidacloprid soil injection was slower to act systemically, but has potential for longer-term activity. Researchers suggest the combination of tree and soil injection for immediate and long-term (4+ years) activity as an effective and economic strategy to protect high-value trees.

Seed bank persistence of genetically modified canola in California

Canola, which is genetically modified (GM) for tolerance to glyphosate, has the potential to become established as a new glyphosate resistant weed, thus reducing the effectiveness of glyphosate. Volunteer from dormant canola seeds produced thousands of plants per hectare in the fourth year (2011) following a 2007 crop harvest. This occurred with no additional canola seed production since the 2007 harvest. Volunteer plants following harvests of annual crops are typically only a problem for the first year after harvest. In California, glyphosate is the core herbicide on over a million hectares of high value row, tree, and vine crops and new glyphosate resistant weeds reduce the effectiveness of glyphosate. The combination of dormant seed and herbicide resistance makes GM glyphosate-resistant canola a new and difficult California weed which was first observed in the winter of 2009.

Somatic Embryogenesis as a tool for forest tree improvement: a case- study in Eucalyptus globulus

Background Somatic embryogenesis (SE) technology is expected to play a significant role in future forest tree improvement programs. Methods for efficient SE propagation in softwood species based on bioreactors are underway [1]. Furthermore, genetic transformation through SE is also the most promising approach to generate and propagate elite recalcitrant genotypes of forest trees [2], or clonal propagation of selected endangered high-value forest trees [3,4]. Somatic embryogenesis induction was first reported for the genus Eucalyptus in 1980. Mass production of SE plants however remains difficult although procedures designed for plant regeneration have been reported for E. citriodora, E. grandis, E. tereticornis[5]. Recent data on E. globulus are promising and show the potential of this technology for application in clonal forestry [6,7]. A service platform for routine transformation of forest trees has been established at the Berzelii Center at Umea Plant Science Centre using Norway spruce as the primary model species for gene function analyses. Other target species for future studies include hardwood species such as Poplar and Eucalyptus. We present here a brief summary of a case study for introduction of a recalcitrant forest species to the platform as demonstrated by the establishment of the SE technology for E. globulus following protocol previously established in Portugal [6,7] and preliminary results aiming to improve the induction of SE.

Options for control of scolytid beetles that attack pines.

Abstract Scolytid beetles (Coleoptera: Curculionidae: Scolytinae) are a large group of beetles associated with many tree species. Some species consume dead wood and vector an array of fungi which contribute to recycling of organic material, so are often an important component of forest ecology. However, populations can increase to pest levels. In this review, we look at options for control of scolytid pests of Pinus spp. Pines, valued for their softwood and pulp, are grown commercially in many countries. Both indigenous and exotic species of bark beetle are pests of pines. There have been numerous approaches to reducing the impact of bark beetle attack on pines. Management strategies have included thinning stands and timing of harvesting and planting, through to efforts to predict outbreaks. Bark beetles use semiochemicals to locate hosts and attract conspecifics and these have been used to trap or repel beetles, or disrupt their behaviour. Chemical pesticides have been used, especially for protection of high-value trees. Pesticides can be effective in some situations, but the commonly used actives such as organophosphates and pyrethroids have non-target and other health and safety concerns. There have been few successful introductions or applications of natural enemies (predators, parasitoids and microbial pathogens) reported for scolytid pests of pines. The cryptic, within-tree, habitats used for much of the bark beetle life cycle provide significant protection against most forms of control. Successful control will require novel approaches and will likely involve multiple agents and strategies.

Impact of site and provenance on economic return in Nordmann fir Christmas tree production

The economic potential of 35 seed lots from Danish landraces of Nordmann fir [Abies nordmanniana (Stev.) Spach.] and seven imported provenances were evaluated for high-value Christmas tree production over a full rotation at six locations in Denmark. Naturally grown Christmas trees were evaluated and no leader length control or trimming of the side branches was allowed, but only simple cutting of double terminal leaders. Seed source as well as site strongly affected the economic revenue. Average net sales price per planted tree ranged over sites from €2.43 to €6.64, and among provenances from €1.38 to €7.06 with an average of €4.95. Changes in prices and grading as seen under cycling market conditions seemed not to affect the economic ranking of the better part of the provenances, whereas discounting the net sales income caused moderate rank changes, reflecting differences in rotation time. Limited seed source by site interactions were present and mainly caused by the slowest growing sources. Among the Danish domesticated seed sources of mostly unknown origin several were as suitable as the tested imported sources. In general, the Danish sources were faster growing than imports, although very large variation was present.

A COMPARISON OF FOUR PRE-PLANT SOIL TREATMENTS FOR CONTROL OF VERTICILLIUM WILT IN FIELD-GROWN TREES

Verticillium wilt is a serious disease of several high-value ornamental tree species grown as field crops. The causal fungus Verticillium dahliae is widespread in UK soils. Until 2006, land was generally treated with methyl bromide before planting species susceptible to Verticillium wilt in order to reduce risk of the disease. A field experiment was done to determine effectiveness of four potential alternative pre-plant soil treatments for control of Verticillium wilt in Acer platanoides and Tilia cordata. The experiment was established in 2005 on land naturally infested with V. dahliae at a mean level of 15 cfu (microsclerotia)/g, as determined by a soil-plating test. Pre-plant soil treatments were: 1. Untreated fallow (control); 2. Sudan grass grown on site and incorporated as a green manure; 3. Biological Soil Disinfestation (BSD) using Italian rye-grass; 4. KS 5. Basamid (dazomet) incorporated to 20 cm depth applied simultaneously with Sistan 51 (metam sodium) injected at 25-35 cm depth. Basamid/Sistan 51, KS sudan grass was ineffective. In spring 2006, the land was planted with two Verticillium susceptible species, A. platanoides ‘Emerald Queen’ and T. cordata ‘Greenspire’. Bark cracking in Acer first occurred in 2007, the second growing season after planting. This symptom of Verticillium wilt was significantly reduced by Chlorofume (8%) and Basamid/Sistan 51 (6%) soil treatments compared with the untreated control (22%). No definitive symptoms of Verticillium wilt occurred in Tilia at this time. In autumn 2007, one-third of the trees were cut down and the stem bases tested for V. dahliae by isolation onto agar. The fungus was recovered from 35% of Acer and 18% Tilia trees on untreated land. The incidence of infection in Acer was significantly reduced by Chlorofume (16%) and Basamid/Sistan (17%); the incidence of infection in Tilia was reduced by the two chemical treatments (nil infection) and BSD (9%). Levels of infection in Tilia were greater in 2008 than in 2007, with some diseased trees in all treatments. The incidence of tree infection is discussed in relation to the level of soil infestation with V. dahliae at planting.

Crataeva nurvala: A Valuable Medicinal Plant

Crataeva nurvala Buch. Ham. (Capparaceae) is a high-value medicinal tree that grows almost all over India, especially in the semiarid regions. Medicinal usage has been reported in traditional systems of medicine, such as Ayurveda and Unani, wherein the plant is frequently preferred in the treatment of urinary disorders that reoccur owing to development of antibiotic resistance by the infecting organism. C. nurvala has also been used in the treatment of prostate enlargement and bladder sensitivity. The plant is known to relieve, prevent, and promote the discharge of kidney stones. Lupeol, a pentacyclic triterpene isolated from the root bark, has been shown to significantly minimize the deposition of stone-forming constituents in kidneys. Investigations have also indicated the plant has anti-arthritic, hepatoprotective, and cardio-protective actions. These multiple uses of C. nurvala along with erratic seed germination, destructive harvesting, and habitat loss from deforestation have endangered survival of the plant. As a result of this endangerment, in India the plant has been categorized as rare or vulnerable in the natural environment, making conservation of this plant crucial. This review briefly examines the biological activities, pharmacological actions, clinical studies, and medicinal applications of C. nurvala to provide direction for further research.

Suppression of <I>Ennomos subsignaria</I> (Lepidoptera: Geometridae) on <I>Acer pseudoplatanus</I> (Aceraceae) in an Urban Forest with Bole-Implanted Acephate

Trees in an urban forest are highly valued because they have esthetic appeal, provide shade, and improve air quality. During the past 5 yr (2002-2006) in St. John's, Newfoundland and Labrador, Canada, the elm spanworm, Ennomos subsignaria (Hübner) (Lepidoptera: Geometridae), has reached outbreak densities. Each year, hundreds of trees have been completely defoliated, and many more trees have been partially defoliated. Adding to this problem, the larvae, their silk strands, and their frass are a considerable nuisance to property owners in areas of high larval densities. In this study, we evaluated the efficacy of three doses of bole-implanted acephate (AceCap 97) for reducing densities and associated defoliation of E. subsignaria on sycamore maple, Acer pseudoplatanus L. (Aceraceae). During the treatment year (2005), all three doses significantly reduced E. subsignaria larval and pupal density; full or two-thirds doses significantly reduced defoliation compared with control trees. During the posttreatment year (2006), bole-implanted acephate did not affect E. subsignaria egg mass density, survival (= adult emergence), or defoliation. Bole-implanted acephate is an effective and practical way of suppressing E. subsignaria densities and herbivory in an urban forest where the protection of high-value trees and the reduction of environmental contamination are of utmost importance.

Suppression of Ennomos subsignaria (Lepidoptera: Geometridae) on Acer pseudoplatanus (Aceraceae) in an Urban Forest with Bole-Implanted Acephate

Trees in an urban forest are highly valued because they have esthetic appeal, provide shade, and improve air quality. During the past 5 yr (2002–2006) in St. John’s, Newfoundland and Labrador, Canada, the elm spanworm, Ennomos subsignaria (Hübner) (Lepidoptera: Geometridae), has reached outbreak densities. Each year, hundreds of trees have been completely defoliated, and many more trees have been partially defoliated. Adding to this problem, the larvae, their silk strands, and their frass are a considerable nuisance to property owners in areas of high larval densities. In this study, we evaluated the efficacy of three doses of bole-implanted acephate (AceCap 97) for reducing densities and associated defoliation of E. subsignaria on sycamore maple, Acer pseudoplatanus L. (Aceraceae). During the treatment year (2005), all three doses significantly reduced E. subsignaria larval and pupal density; full or two-thirds doses significantly reduced defoliation compared with control trees. During the posttreatment year (2006), bole-implanted acephate did not affect E. subsignaria egg mass density, survival (=adult emergence), or defoliation. Bole-implanted acephate is an effective and practical way of suppressing E. subsignaria densities and herbivory in an urban forest where the protection of high-value trees and the reduction of environmental contamination are of utmost importance.

Injected Treatments for Management of Madrone Canker

Pacific madrone (Arbutus menziesii) has been experiencing a decline in the Puget Sound area, primarily as a result of a canker disease caused by the fungus Fusicoccum arbuti. Cultural methods such as prevention of stress and wounding are recommended to control canker diseases on trees. In addition to these, injected treatments can be used to protect valuable Pacific madrone trees in urban areas. An experiment testing injectable chemical fungicides and plant activators was performed on Pacific madrone trees inoculated with F. arbuti. There was little correlation between fungicidal activity in culture and canker reduction in the field tests. Two treatments that were effective in minimizing canker growth in inoculated madrones were Arbotect® (Syngenta Crop Protection Inc., Greensboro, NC, U.S.; a triazole fungicide) and BioSerum™ (phosphorous acid). Cankers on wound inoculations were 50% smaller than the control group and no infections occurred on surface-inoculated treatments. Increased callusing was observed on cankers on trees with these treatments and the mode of action for these chemicals is probably stimulation of plant defenses rather than fungicidal action. Phosphorous acid is recommended in addition to cultural methods that improve tree vigor for high-value madrone trees in urban landscapes; however, heavily infected trees that have lost most of their crown will probably not benefit.

Cavity Trees, Snags, and Selection Cutting: A Northern Hardwood Case Study

Abstract Although traditional application of the selection system includes a focus on high-value trees that may reduce cavities and snags, few studies have quantified those habitat features in managed uneven-aged stands. We examined the effects of single-tree selection cutting on cavity trees and snags in a northern hardwood stand immediately prior to the second cutting. Marking followed guidelines proposed by Arbogast, C., Jr. (1957. Marking guides for northern hardwoods under selection system. US For. Serv. Res. Pap. 56, Lake States Forest Experiment Station. 20 p.), with the objective of improving stand quality for timber production while maintaining a balanced diameter distribution. The stand contained seven species of cavity trees and snags; sugar maple and American beech were most common, the latter comprising 20% of snags and 26% of cavity trees despite its relatively minor (7%) contribution to stand basal area. We found that 92% of cavity trees were live, underscoring the value of living trees as sources of cavities. Precut cavity tree density (25.2 live cavity trees per hectare) was more than twice that found in other studies of selection stands, although density of snags (11.0 snags per hectare) was comparable or lower. More than 50% of sampled cavity trees were designated for removal in the second selection cut, reducing projected postcut density to 11.0 live cavity trees per hectare, a density similar to that found in other studies. Postcut density of large cavity trees (3.3 live trees >45 cm dbh per hectare) exceeded published guidelines for northern hardwoods (0.25 to 2.5 live cavity trees >45 cm dbh per hectare). We speculate that the relatively high maximum diameter (61 cm dbh) and long cutting cycle (20 years) used to define the target stand structure may have contributed to the number of cavity trees observed. Nevertheless, selection cutting as applied in this study will likely reduce cavity abundance unless retention of trees with decay is explicitly incorporated into the management strategy.

Effects of an African Weaver Ant, <I>Oecophylla longinoda</I>, in Controlling Mango Fruit Flies (Diptera: Tephritidae) in Benin

Six mango, Mangifera indica L., plantations around Parakou, northern Benin, were sampled at 2-wk intervals for fruit fly damage from early April to late May in 2005. Mean damage ranged from 1 to 24% with a weaver ant, Oecophylla longinoda (Latreille), being either abundant or absent. The fruit fly complex is made up of Ceratitis spp. and Bactrocera invadens Drew et al., a new invasive species in West Africa. In 2006, Ceratitis spp. peaked twice in the late dry season in early April and early May, whereas B. invadens populations quickly increased at the onset of the rains, from mid-May onward. Exclusion experiments conducted in 2006 with 'Eldon', 'Kent', and 'Gouverneur' confirmed that at high ant abundance levels, Oecophylla significantly reduced fruit fly infestation. Although fruit fly control methods are still at an experimental stage in this part of the world, farmers who tolerated weaver ants in their orchard were rewarded by significantly better fruit quality. Conservation biological control with predatory ants such as Oecophylla in high-value tree crops has great potential for African and Asian farmers. Implications for international research for development at the Consultative Group on International Agricultural Research level are discussed.

Effects of an African Weaver Ant, Oecophylla longinoda, in Controlling Mango Fruit Flies (Diptera: Tephritidae) in Benin

Six mango, Mangifera indica L., plantations around Parakou, northern Benin, were sampled at 2-wk intervals for fruit fly damage from early April to late May in 2005. Mean damage ranged from 1 to 24% with a weaver ant, Oecophylla longinoda (Latreille), being either abundant or absent. The fruit fly complex is made up of Ceratitis spp. and Bactrocera invadens Drew et al., a new invasive species in West Africa. In 2006, Ceratitis spp. peaked twice in the late dry season in early April and early May, whereas B. invadens populations quickly increased at the onset of the rains, from mid-May onward. Exclusion experiments conducted in 2006 with ‘Eldon’, ‘Kent’, and ‘Gouverneur’ confirmed that at high ant abundance levels, Oecophylla significantly reduced fruit fly infestation. Although fruit fly control methods are still at an experimental stage in this part of the world, farmers who tolerated weaver ants in their orchard were rewarded by significantly better fruit quality. Conservation biological control with predatory ants such as Oecophylla in high-value tree crops has great potential for African and Asian farmers. Implications for international research for development at the Consultative Group on International Agricultural Research level are discussed.