Pine wilt disease caused by the pinewood nematode (PWN), Bursaphelenchus xylophilus (Steiner et Buhrer) Nickle, has destroyed huge areas of pine forest in East Asia, including Japan, China and Korea. No protection against PWN has been developed, and the responses of pine trees at the molecular level are unrecorded. We isolated and analyzed upregulated or newly induced genes from PWN-inoculated Japanese red pine (Pinus densiflora Sieb. et Zucc.) by using an annealing control primer system and suppression subtractive hybridization. Significant changes occurred in the transcript abundance of genes with functions related to defense, secondary metabolism and transcription, as the disease progressed. Other gene transcripts encoding pathogenesis-related proteins, pinosylvin synthases and metallothioneins were also more abundant in PWN-inoculated trees than in non-inoculated trees. Our report provides fundamental information on the molecular mechanisms controlling the biochemical and physiological responses of Japanese red pine trees to PWN invasion.

This chapter provides a practical worldwide overview of the environmental applications of poplars and willows. The chapter aims to synthesize the latest knowledge on these applications with respect to sustainable livelihoods, land use and restoration. The applications covered include land protection, watershed stabilization, waste management and other ecosystem services.

Six pine species or hybrids were tested for susceptibility to pitch canker caused by Fusarium circinatum. Pinus densiflora, Pinus thunbergii, Pinus x rigitaeda (Pinus rigida · Pinus taeda), P. rigida · P. x rigitaeda, Pinus echinata and Pinus virginiana were inoculated with three spore loads (50, 500 and 5000 per tree) of F. circinatum. External symptoms, lesion length, and the frequency of reisolation of the fungus were investigated. External symptoms were greatest in P. echinata, followed by P. virginiana, however, P. densiflora was not susceptible to F. circinatum. Based on mean lesion lengths, the six pine species or hybrids differed significantly (p < 0.01) in susceptibility to pitch canker. Pinus echinata sustained the longest lesions, whereas P. densiflora sustained the shortest lesions. The effect of inoculum density was not significant among three spore treatments within species (p = 0.17), although lesion length was slightly greater at higher spore loads over all pine species. The fungus was reisolated from inoculated stems of all pine species tested, even on trees showing little or no damage from the disease. Additional studies are needed to further explore the basis for resistance to pitch canker.

Stability parameters and clone x site interactions for 12-year volume were investigated in seven Populus davidiana (Korean aspen) clonal trials in South Korea. Either 24 or 38 clones were tested in each of the seven sites. All sources of variables such as clone, site, and clone x site interaction were statistically significant (p < 0.01) in the analysis of variance. The average volume of 3,199 trees was 0.043 m 3 . The different types of stability were shown from selected clones against the test means for volume. Clone Palkong 2 represents a relatively unstable clone that is sensitive to site changes and had greater adaptability to favorable sites.Five clones, Odae 19, Taehyun 9, Sunyeo 4, Sokwang 31, and Taehyun 3, were selected as superior clones based on stability parameters and mean volume. The selected clones have average stability and performed in a predictable manner over different planting sites. A positive relationship between stability parameters and the clone mean performance for volume was noted in this study.

Abstract• Seedlings of seven pine species or hybrids, Pinus densiflora, Pinus thunbergii, Pinus virginiana, Pinus echinata, Pinus koraiensis, Pinus thunbergii × Pinus massoniana and Pinus × rigitaeda, were inoculated in a greenhouse with 100, 1 000 and 10 000 pathogenic nematodes, Bursaphelenchus xylophilus, to compare initial symptom development and to evaluate susceptibility to pinewood nematodes.• Genetic types were significantly different in the starting day of needle discoloration (χ 2 = 43.48; P < 0.001) and the period from nematode inoculation to seedling death (χ 2 = 32.85; P < 0.001), but treatment groups were not statistically different in the days from inoculation to seedling death in any of the pine species.• There was no relationship between seedling mortality and the number of nematodes recovered from infected seedlings. Only eight of the nematode-inoculated seedlings remained alive by day 83 after inoculation, including four seedlings each of P. echinata and P. × rigitaeda grown from bulked seed collections.• Seedlings from the bulk lots were likely more genetically diverse than those from the single-source lots. A broader genetic representation of pine species or hybrids is suggested for screening for planting stocks resistant to B. xylophilus. Mots-clés :nématode du pin / sensibilité / inoculation / Bursaphelenchus xylophilus / mortalité Résumé -Inoculation sous serre de semis de sept espèces ou hybrides de pin par des isolats coréens du nématode du pin.• Des semis de sept espèces ou hybrides de pin, Pinus densiflora, Pinus thunbergii, Pinus virginiana, Pinus echinata, Pinus koraiensis, Pinus thunbergii × massoniana, et Pinus × rigitaeda ont été inoculés sous serre par 100, 1000 ou 10 000 nématodes pathogènes Bursaphelenchus xylophilus, pour comparer le développement des symptômes à leur début et évaluer la sensibilité de ces essences.• Des différences significatives ont été trouvées entre types génétiques pour la date de début de déco-loration des aiguilles (χ 2 = 43.48 ; P < 0.0001), ainsi que pour le délai entre l'inoculation et la mort des plants (χ 2 = 32.85 ; P < 0.0001), mais pas entre traitements, quelle que soit l'espèce.• Aucune relation n'a été observée entre la mortalité des semis et le nombre de nématodes récupérés des semis infestés. Seulement huit plants inoculés étaient encore vivants après 83 jours, dont quatre de P. echinata et de P. × rigitaeda issus des collections de graines en vrac.• Les semis des lots de vrac étaient probablement génétiquement plus variés que ceux des lots de source unique. Une plus large représentation des espèces et des hybrides serait nécessaire pour un screening des souches de plantations résistantes à B. xylophilus.