Oliver Dünisch

Dendroecological investigations on Swietenia macrophylla King and Cedrela odorata L. (Meliaceae) in the central Amazon

The width of the increment zones in the xylem of Swietenia macrophylla King and Cedrela odorata L. was investigated by dendroecological methods in a primary forest near Aripuanã, Mato Grosso, Brazil (10°09′S, 59°26′W). The annual period of cambial cell division and its intra-annual variation were determined by dendrometer measurements of 30 trees of each species. Tree-ring width chronologies for Swietenia and Cedrela were developed from cross-dated increment curves of 33 out of 47 Swietenia and 51 out of 64 Cedrela trees. Simple correlations were computed between the radial growth increment and monthly precipitation for the period 1890–2000. In Swietenia, cambium activity occurred throughout almost the whole year, but in Cedrela it was restricted to the rainy period from September of the previous year to June of the current year. Tree-rings were formed annually in the juvenile and adult wood of Cedrela, while in Swietenia the annual formation of tree-rings was restricted to the adult wood. Consequently the age of the Swietenia trees could be dated by the tree-rings in good approximation, while age dating of the Cedrela trees was exact. Correlation analyses revealed a significant relationship between the precipitation at the beginning and at the end of the growth season and the width of the increment zones in the adult xylem of Swietenia. In contrast, the width of the growth increment in the xylem of Cedrela was significantly correlated with the precipitation in March and May of the previous growth period.

FORMATION OF INCREMENT ZONES AND INTRAANNUAL GROWTH DYNAMICS IN THE XYLEM OF SWIETENIA MACROPHYLLA, CARAPA GUIANENSIS, AND CEDRELA ODORATA (MELIACEAE)

The pattern of growth increment zones, the cambial growth dynamics and the structural variation in wood formation of Swietenia macrophylla King, Carapa guianensis Aubl., and Cedrela odorata L. (Meliaceae) were investigated in order to understand the relationship of site conditions and sustainable growth in Central Amazonian plantations. Trees were available from 8-, 17-, 23-, and 57-year-old plantations, and from primary forests in Manaus (Amazonia), Santarem (Para), and Aripuana (Mato Grosso). The wood anatomical structure and the annual increments of 61 Swietenia, 94 Carapa, and 89 Cedrela trees were studied for different tree heights. The curves of annual increments were cross-dated and tested for synchronisation. The cambial growth dynamics of up to 52 trees per species were dated by means of dendrometer measurements, monthly labelling by pinmarkers, and extracted cambium samples investigated using a microscope. The intraannual course of the growth and structural variation was compared with the water supply of the soil and insect attacks (Hypsipyla grandella (Zeller) Lep.).In Swietenia and Carapa parenchyma and vessel bands as well as bands of resin canals were observed. Within the xylem of Cedrela, alternating bands of fibres and vessels surrounded by paratracheal parenchyma were found; bands of resin canals were only occasional. In the juvenile wood of Swietenia and Carapa no synchronization of the increment curves was possible, whereas the increment curves obtained in the juvenile wood of Cedrela showed parallel run in growth. The increment curves obtained in adult wood of Swietenia and Cedrela indicate an annual formation of increment zones, whereas the number of increment zones in the xylem of Carapa was approximately 50% higher than the tree age (years) indicating that the growth increments of Carapa also were not annual during the adult phase of growth.The study of the intraannual growth dynamics of the trees showed that the formation of parenchyma bands in Swietenia is induced by dry periods before a cambial dormancy. The formation of parenchyma bands of Carapa was induced by extremely dry and extremely wet periods before a cambial dormancy, whereas fibre bands in Cedrela were induced by dry periods before a cambial dormancy and the formation of vessel bands embedded in paratracheal parenchyma was induced by wet periods after a cambial dormancy. In addition, insect attack (Hypsipyla grandella) induced locally restricted formation of parenchyma bands and bands of resin canals in Swietenia, Carapa and Cedrela.

COMPARISON OF GROWTH DYNAMICS AND WOOD CHARACTERISTICS OF PLANTATION-GROWN AND PRIMARY FOREST CARAPA GUIANENSIS IN CENTRAL AMAZONIA

This study responds to the demand for recultivation of degraded land areas in Central Amazonia and the desire to add long-lived trees for high-quality timber production to polyculture plantation systems. Carapa guianensis Aubl. from two monocultures (ages 4 and 17 years) and a primary forest were studied. The growth dynamics of the 4-yearold trees revealed 11 to 15 increments marked by tangentially oriented vessel rows. By the 5th year, parenchyma bands indicate mature wood. Monthly labelling by pin-markers revealed short dormancy periods during the dry season. The early formation of mature wood is shown by the pattern of percentage composition of vessels, fibres, and parenchyma. Fibre length reaches its plateau of 1.45–1.59 mm at about four years. Fibre lengths and average density (0.63 g /cm3) of plantation-grown trees correspond to those of primary forest trees. According to this study, Carapa guianensis can be recommended for plantations in order to produce high-quality timber with a decorative heartwood.

Chloroplastid pigment contents and chlorophyll a fluorescence in Amazonian tropical three species

ABSTRACT – Plants react to changes in light and hydrological conditions in terms of quantity and compositionof chloroplastidic pigments, which affects the photosynthetic properties and consequently the accumulationof plant biomass. Thus, the chloroplastidic pigment concentration and chlorophyll a fluorescence of threeAmazonian species ( Bertholletia excelsa, Carapa guianensis e Dipteryx odorata ) were investigated in sunand shade leaves form the tree crown collected during two distinct periods of precipitation (dry and rainyseasons). Pigment contents were determined by spectrophotometry and fluorescence variables were determinedusing a portable fluorometer. The results demonstrated that the species showed high concentrations of Chla, Chl b e Chl total during the wet season in relation to the dry season, especially in shade leaves. A higherconcentration of carotenoids was found in B. excelsa , when compared with leaves of C. guianensis and D.odorata . In leaves of B. excelsa and D. odorata

Retention properties of wood residues and their potential for soil amelioration

The particle size distribution, the nutrient content and the sorption behaviour of six solid wood and ash/charcoal residues collected in three wood-processing companies in Germany and Brazil were investigated in order to elucidate the potential of these residues for the development of new products for soil amelioration. The absorption of N, P, and K by the residues and the leaching of nutrients from impregnated samples were studied in the laboratory at substrate temperatures of 20 and 300°C. The release of elements by the impregnated samples and the sorption behaviour of ash/charcoal incorporated in the soil were also studied in the field on a temperate site (Hamburg, 53°32′N 09°59′E), on a subtropical site (Ivaí, 25°15′S 50°45′W), and on a tropical site (Aripuanã, 10°09′S 59°26′W). Under laboratory conditions the solid wood residues absorbed 2.0–9.1% of the N, 0.1–0.4% of the P, and 1.0–8.5% of the K available in the impregnation solution. At a temperature of 20°C, selected sieve fractions of the ash/charcoal residues absorbed up to twice as much as N and up to 100 times more K than the treated wood residues. The absorption of N, P, and K to the ash/charcoal residues increased significantly at a substrate temperature of 300°C compared to a substrate temperature of 20°C. In absolute numbers, the leaching of N, P, and K from the impregnated ash/charcoal residues was in the range of the release by the impregnated solid wood residues, whilst the relative rate of nutrient leaching was strongly reduced. The field experiments confirmed the results obtained in the laboratory and indicated that ash/charcoal residues are suitable raw materials for the development of new products for soil amelioration, in particular for application under humid climate conditions.

Chemical composition and natural durability of juvenile and mature heartwood of Robinia pseudoacacia L.

The aim of this study was to characterize the properties of juvenile and mature heartwood of Robinia pseudoacacia L. (black locust). The content, the composition, and subcellular localization of heartwood extractives were studied in 14 old-grown trees from forest sites in Germany and Hungary, as well as in 16 younger trees of four clone types. Heartwood extractives (methanol and acetone extraction) were analysed by HPLC-chromatography. UV microspectrophotometry was used to localize the extractives in the wood cell walls. The natural durability of juvenile and mature heartwood was analysed according to the European standard EN 350-1. Growth analyses, as well as the chemical analyses, showed that in Robinia the formation of juvenile wood is restricted to the first 10-15 years of cambial growth. In the heartwood high contents of phenolic compounds and flavonoids were present, which were in high concentrations in the cell walls of the axial parenchyma and of the vessels. In the juvenile heartwood, the content of these extractives is significantly lower than in the mature heartwood. In agree, the juvenile heartwood had a lower resistance to decay by Coniophora puteana (brown rot fungus) and Coriolus versicolor (white rot fungus) compared to the mature.

Sekundäre Veränderungen im Holz akut belasteter Fichten (Picea abies [L.] Karst.) in Hochlagen des Osterzgebirges

ZusammenfassungIm Rahmen eines vom Bundesministerium für Bildung, Wissenschaft, Forschung und Technologie (BMBF), Bonn, interdisziplinär ausgerichteten Projektes «Untersuchung von Waldökosystemen im Erzgebirge als Grundlage für einen ökologisch begründeten Waldumbau» war u.a. die Bewertung der Holzqualität von Fichten SO2-belasteter und stark windexponierter Hochlagen von Bedeutung. In der vorliegenden Untersuchung wurde das Holz von 6 stehenden, windexponierten und 6 nach einem Sturmereignis atypisch gebrochenen Fichten untersucht.Mit Hilfe der Polarisationsmikroskopie kombiniert mit Phasenkontrastierung und elektronenmikroskopischen Verfahren wurden die Bildung, Verteilung und Ausdehnung von Mikrostauchlinien «slip planes» in den Zellwänden analysiert und ihre Bedeutung als bruchauslösende Initialstellen quantifiziert. Aus den Bruchzonen wurden holzzerstörende und holzverfärbende Pilze isoliert und taxonomisch bestimmt. Das Ausmaß des Holzabbaus wurde auf zellulärer und subzellulärer Ebene mit Hilfe der Fluoreszenzmikroskopie und UV-Spektroskopie charakterisiert.In den stark SO2-belasteten und aufgelichteten Fichtenbeständen der Hochlagen des Erzgebirges werden durch extreme Windbelastung in einzelnen Bäumen Mikrostauchlinien induziert, die sich im Bereich von Holzstrahlen und Astspuren häuften. Diese Stauchlinien wurden sekundär von holzabbauenden Pilzen, insbesondere durch Stereum sanguinolentum (Alb. et Schw.: Fr.) Fr. besiedelt. In den Zellwänden dieser Zonen war ein simultaner Abbau von Gerüstkohlenhydraten und Lignin nachweisbar. Diese Beeinträchtigung kann bei einzelnen Stämmen kurzfaserige, treppenförmige Windbrüche verursachen. Bei einer verbesserten Bestandesstruktur bei zugleich rückläufiger SO2-Immission verdient die Fichte aus Sicht der erreichbaren Holzeigenschaften weiterhin Berücksichtigung.AbstractWithin the framework of an interdisciplinary research project “investigation of forest ecosystems in the ore-mountains as basis for an ecologically oriented silviculture” supported by the Federal-ministry for education, science, research and technology (BMBF), Bonn, a study of the wood quality of heavily SO2-polluted and wind-exposed spruce trees from high altitude stands was conducted. For this study wood from 6 standing, wind-exposed and 6 storm-tossed trees with brash fractures was considered. By means of light microscopy (polarization, phase contrast) and electron microscopy the formation, distribution and extension of slip planes within the cell walls were examined and their significance for fracture initialization quantified. Wood discolouring and wood destroying fungi were isolated from the fracture zones and taxonomically determined. The extent of wood decay was characterized on a cellular and subcellular scale by means of fluorescence microscopy and UV spectroscopy.In the heavily SO2-polluted and thinned-out spruce stands at the high altitudes of the ore-mountains extreme wind stresses initiate in some tress slip planes which accumulate in the vicinity of rays and branch tracers. The slip plane zones are subsequently infected by wood degrading fungi, in particular by Stereum sanguinolentum (Alb. et Schw.: Fr.) Fr. resulting in a simultaneous decay of carbohydrates and lignin in the cell walls. The combined effect of wind stress and cell-wall degradation apparently induces brash, staircase-like fractures in some stems, which limitates the utilization of the timber. Eventually reduced SO2 immissions and an improved stand structure will help avert this kind of damage and spruce grown at this site will again satisfy standard wood quality requirements.

Low night temperatures cause reduced tracheid expansion in Podocarpus latifolius.

The influence of low night temperatures on the kinetics of tracheid expansion of two-year-old Podocarpus latifolius (Thunb.) R.Br. ex Mirb. was studied in a growth chamber experiment. In experiment 1 the plants were exposed to an almost constant air temperature of 18 to 20°C, while in experiment 2 the air temperature was reduced from 20°C during the day to 6°C during the night. The formation of the cambium derivative cells and the kinetics of tracheid expansion were analysed by high resolution laser increment measurements in combination with microscopic methods (accuracy: ± 2 μm, spatial resolution of 9.7 to 13.1 μm, temporal resolution: 60 s). Low night temperatures had no significant influence on the rate of cambial cell divisions and the proportion of tracheids and parenchyma cells in the xylem. However, they irreversibly interrupted the expansion of differentiating tracheids causing a high proportion of flattened tracheids in the xylem of the plants grown under the conditions of experiment 2. The results indicate that large differences between day and night temperatures can be an important trigger for the variation of the wood structure in subtropical and tropical gymnosperms.

Nutrient fluxes and growth of Carapa guianensis Aubl. in two plantation systems in the central Amazon

Abstract The K, Mg, and P fluxes as well as the growth dynamics of the important timber tree Carapa guianensis Aubl. were compared in a monoculture and in an enrichment plantation on a “terra firme” site near Manaus, central Amazon. During the 7 years experimental period, the K, Mg, and P fluxes and the balance of the soil were quantified for monthly intervals. The nutrient input into the soil was calculated from the wet and dry deposition as well as from litter decomposition. The nutrient output out of the soil was calculated from the net nutrient uptake of the vegetation and the nutrient leaching from the soil. The growth dynamics of the planted trees were studied by means of biomass data obtained from dendrometric measurements and total tree harvesting. After 7 years of growth, the K, Mg, and P balance of the soil of the enrichment plantation was stabilised, whereas a significant deficit of the K, Mg, and P balance of the soil of the monoculture became obvious, caused by high leaching of K and Mg from the soil and low litter decomposition rates. Due to strong competition during the first 5 years of growth, a reduced biomass production of the planted Carapa trees was found in the enrichment plantation compared to trees grown in the monoculture. After that period tree growth was strongly reduced in the monoculture, whereas after 7 years, growth of Carapa grown in the enrichment plantation was still steady. From this study, it was concluded that due to the balanced K, P, and Mg input and output of the soil and more sustainable growth of the planted trees in the enrichment plantation compared to the traditional monoculture, the cultivation of Carapa for timber production is recommended in diverse plantations, such as enrichment plantations on this study site.

VARIABILITY OF VESSEL CHARACTERISTICS IN THE XYLEM OF ILEX PARAGUARIENSIS (MATÉ-TREE) FROM SOUTH BRAZIL

SUMMARY In this study the wood anatomy of two leaf-morphotypes (“Yellow” and “Grey”) of Ilex paraguariensis St. Hil. (Aquifoliaceae) from South Brazil was compared with special attention to vessel attributes and a possible relationship of leaf morphology and wood structure. Sampling was carried out in a 15-year-old plantation in the state of Parana, South Brazil. The anatomy of the juvenile and mature wood of five male and five female plants of each morphotype was investigated by light microscopy. In all plants the increment and the proportion of vessels decreased from pith to cambium, while vessel element length increased. Plants of the morphotype “Grey” had shorter vessel members (157–382 μm) and a lower number of bars per perforation plate (14–15) compared to the plants of the morphotype “Yellow” (vessel member length: 304–567 μm, bars: 22–24). No significant differences were found between the wood of male and female plants.