Early plant biomass trends following forest site preparation on the Oregon Coast Range

The vegetation following forest site preparation was examined in ten clearcut units located in the western Oregon Coast Range. The site preparation techniques used in these units included scarification, slash burning, and chemical spraying. The ages of the clearcut units studied varied from one to nine growing seasons for the scarification treatment, two to ten for the slash burning treatment, and two to six for the spraying treatment. The survey of the vegetation was executed during the summer of 1976. Herbaceous and shrub vegetation were characterized by biomass and cover measurements together with the identification of the three principal species in each vegetation layer. In addition, the influence of the density of the previous conifer stand on the occurrence and abundance of shrub individuals following site preparation and the activity of browsers on both planted coniferous transplants and shrub stems were examined. Results were evaluated in relation to the rate of reoccupancy of the site by herbaceous and shrub vegetation. This was used in an attempt to conceptualize the relative roles of both components of the system in the early stages of succession, and to determine the strategies of these vegetation components as secondary plant succession progresses. The vegetation on a clearcut unit is made up of several small vegetative units as a consequence of the different intensities of the site preparation method used and is, therefore, variable in structure and composition. Findings indicate that early successional trends are characterized by an increasing abundance of both herbaceous and shrub species in proportions related to the particular set of site conditions imposed by the method of site preparation. In the initial stages of succession, microenvironmental factors under the influence of herbaceous species appear to control the establishment of conifers while by the fourth year increasing influence from the sprouting shrubs usurps a controlling influence on further succession. The suppressive effect of coniferous overstory on understory development of shrubs indicates that intense brush recovery is more likely to happen on sites previously supporting conifer stands of low density. Such a trend, although variable, identifies the desirability of high stand densities on brush threat sites. Selective feeding on coniferous seedlings and on brush sprouts by deer and rodents appears to be an important consideration in long term succession. Animal populations are high in habitats conditioned by site preparation; the vegetation following scarification and slash burning appeared especially attractive to browsers while that after spraying appeared attractive to rodents. Over all, composition of perennials shortly after disturbance, especially sprouting woody species, has a major effect on long-term community development. Selective consumption by deer and rodents can delete components of low abundance, such as conifers, during the early stages of succession. Choice of site preparation method can affect both the composition and the density of woody cover and the apparent degree of animal use

Variation of carbon allocation and competitive ability of different tree species as related to successional position and habitat

Early and late seral tree species were compared for inter-and intraspecific competitive ability; within-population genetic variability; and allocation patterns of soluble sugars and starch seasonally and in response to shade and nitrogen fertilization. Species were Douglas-fir (early seral) and western hemlock (late seral) from a low elevation habitat; and noble fir (early seral) and silver fir (late seral) from a high elevation habitat. Mortality increased with density and peaked at 15% for western hemlock, 35% for Douglas-fir, 48% for noble fir, and 90% for silver fir. In general, early seral species grew faster and attained larger final size than late seral species, while species did not differ in response to competition. However, there were considerable differences among half-sibling families within each species. Ranges in average top weights for families grown at low or medium (16 or 4 cm2 of initial growing space) were: western hemlock, 50-300 mg; Douglas-fir, 100-900 mg; silver fir, 10-190 mg; noble fir, 90-250 mg. Root size was less variable resulting in highly significant density-correlated rank changes in shoot/root ratio (S/R ratio) for families of all species except noble fir. Western hemlock grown with Douglas-fir had shoots 24% smaller and roots 36% smaller than when grown with other western hemlock and Douglas-fir roots were 40% larger when grown with a mixture of Douglas-fir and western hemlock than when grown entirely with one species or the other. Families of both species differed in their SIR ratio response to varying neighbor composition. In contrast, neighbor composition had little effect on silver fir and noble fir. Field-grown seedlings were 30% smaller and less responsive to treatments than pot-grown. In all species, 66 to 70% of total dry weight was soluble sugars and starch prior to budbreak with roughly two-thirds of this as starch. Following budbreak, available carbohydrates decreased to 25 to 30% of total dry weight (maintained through the growing season). Late seral species had higher root sugars during the growing season than early seral species. Shading either decreased or did not affect growth of early seral species and increased growth of late seral species. It had little effect on available carbohydrates. Nitrogen fertilization increased SIR ratio of western hemlock from 1.9 to 3.3 and of the other species from 1.2 to 2.2; and reduced sugar concentration in all species but had little effect on starch. Family variances in prebudbreak root sugars were 17 times greater in western hemlock than in Douglas-fir and noble fir. Family variance in growth traits was greater in the low elevation than in the high elevation species

Efeito do volume do tubete no crescimento inicial de plântulas de Cordia trichotoma (Vell.) Arrab. ex Steud e Jacaranda micranta Cham.

This study compared the effects of container volume upon initial seedling growth of Cordia trichotoma (Vell.) Arrab. ex Steud and Jacaranda micranta Cham. 180 days after the planting. The plastic containers used were filled with commercial nursery substrate and displayed volumes of 55, 120, 180 and 300 cm3. No mortality was recorded among seedlings of all container sizes. There were no statistical differences in respect of height and stem diameter from seedlings cultivated in 120, 180 and 300 cm3 containers 180 days after the planting date.O ensaio comparou os efeitos de tubetes de quatro volumes no crescimento de mudas de Cordia trichotoma (Vell.) Arrab. ex Steud e Jacaranda micranta Cham. até 180 dias após o plantio (DAP). Foram utilizados tubetes plásticos de seção circular e volume de 55, 120, 180 e 300 cm3 preenchidos com substrato comercial. Os resultados indicaram que, durante a fase de viveiro na qual não fora anotada nenhuma mortalidade, os tubetes menores causaram diminuição da massa seca do sistema radicular e do número de radicelas. O crescimento a campo em altura e diâmetro das mudas das duas espécies utilizadas no ensaio resultou em similaridade estatística entre as originadas de tubetes com volumes de 120, 180 e 300 cm3 ao final de 180 dias após plantio

Efeito do tubete no crescimento inicial de Cordia trichotoma (Vell.) Arrab. ex steud e Jacaranda micranta Cham.

Este ensaio comparou os efeitos de quatro tubetes no crescimento de mudas deCordia trichotoma (Vell.) Arrab. ex steud, e Jacaranda micranta Cham. at´e 180 dias ap´oso plantio. Foram utilizados tubetes pl´asticos de se¸c~ao circular e volume de 55 cm3 , 120cm3, 180 cm3, e 300 cm3 preenchidos com substrato comercial. Os resultados indicaramque, durante a fase de viveiro, os tubetes menores causaram diminui¸c~ao da massa seca dosistema radicular e do n´umero de radicelas. O crescimento das mudas de caroba e de louropardoem altura e di^ametro plantadas a campo resultou em similaridade estat´ıstica entre asoriginadas de tubetes de 120 cm3, 180 cm3, e 300 cm3 ao final de 180 dias ap´os plantio. Oplantio de mudas das esp´ecies testadas em solos de boa fertilidade possibilita a utiliza¸c~ao detubetes de 120 cm3 com economia de substrato, de espa¸co de viveiro e de esfor¸co no plantio

Quantifying abiotic stress of plants - advantages and disadvantages of chlorophyll fluorescence Quantificação do estresse abiótico em plantas - vantagens e desvantagens da fluorescência da clorofila

AbstractFluorescence analysis has become a powerful and widely used technique among plant physiologists and ecophysiologists because its measurement bears a relationship to photosynthesis. Therefore, chlorophyll fluorescence (CF) measurements have become a method to study the functioning of the photosynthetic apparatus in response to environmental stress. Light absorbed by plants that does not drive the production of carbohydrates is dissipated as heat or re-emitted as light in the form of fluorescence. Every environmental factor deviating from the optimum constitutes a stress to plants. Consequently, any stress that affects the function of photosystem II and associated de-excitation pathways will have an effect on chlorophyll fluorescence. Measuring CF assesses the efficiency of both photochemistry and non-photochemical processes. This review uses published examples from the literature to discuss advantages and limitations of leaf chlorophyll fluorescence of photosystem II measurements to quantify and to discriminate the effects of various abiotic stresses upon plant growth and development.Resumo A análise da fluorescência tornou-se uma técnica poderosa e amplamente utilizada entre os fisiologistas e ecofisiologistas vegetais, tendo em vista a sua relação com a fotossíntese. Assim, mensurações da fluorescência da clorofila tornou-se uma metodologia amplamente reconhecida para estudar o aparelho fotossintético em resposta ao estresse do ambiente. A luz absorvida e não utilizada pelas plantas na produção de fotoassimilados é dissipada na forma de calor ou reemitida na forma de fluorescência. Qualquer fator do ambiente que se desvie do ótimo constitue-se em um estresse para as plantas. Consequentemente, qualquer estresse que altere o funcionamento do fotossistema II e as rotas de excitação associadas afetará a fluorescência da clorofila. Medir a fluorescência da clorofila avalia a eficiência dos processos fotoquímico e não-fotoquímico. Esta revisão utiliza exemplos publicados na literatura para discutir vantagens e limitações das medições da fluorescência da clorofila utilizadas para quantificar e discriminar os efeitos de vários estresses abióticos sobre o crescimento e desenvolvimento das plantas

Avaliação da arborização urbana pelos residentes - estudo de caso em Mal. Cândido Rondon, Paraná.

Este estudo objetivou quantificar a percepção da arborização urbana da cidade de Mal. Cândido Rondon, Paraná, pelos munícipes residentes. Os dados foram obtidos por meio da aplicação de um questionário a trinta residentes localizados em 53 pontos de amostragem da área urbana do município perfazendo um total de 1.590 entrevistas. Os resultados indicaram que, para 56% da população urbana, a cidade de Mal. Cândido Rondon, assim como a rua de residência do munícipe possuem alguma arborização. Dos entrevistados,  92 % percebem alguma vantagem da presença da arborização sendo que os benefícios  relacionados com o conforto térmico foram os mais lembrados. 75% dos entrevistados declararam sua colaboração na manutenção da arborização urbana. A valoração da arborização urbana pelos munícipes rondonenses refletiu-se no fato de que 91% dos entrevistados se declararem propensos a contribuir anualmente com valores entre R$1,00 e R$ 5,00 para a sua manutenção

EFFECT OF CONTAINER VOLUME ON INITIAL GROWTH OF Cordia trichotoma (Vell.) Arrab. ex Steud AND Jacaranda micranta Cham. SEEDLINGS

O ensaio comparou os efeitos de tubetes de quatro volumes no crescimento de mudas de Cordia trichotoma (Vell.) Arrab. ex Steud e Jacaranda micranta Cham. at\ue9 180 dias ap\uf3s o plantio (DAP). Foram utilizados tubetes pl\ue1sticos de se\ue7\ue3o circular e volume de 55, 120, 180 e 300 cm3 preenchidos com substrato comercial. Os resultados indicaram que, durante a fase de viveiro na qual n\ue3o fora anotada nenhuma mortalidade, os tubetes menores causaram diminui\ue7\ue3o da massa seca do sistema radicular e do n\ufamero de radicelas. O crescimento a campo em altura e di\ue2metro das mudas das duas esp\ue9cies utilizadas no ensaio resultou em similaridade estat\uedstica entre as originadas de tubetes com volumes de 120, 180 e 300 cm3 ao final de 180 dias ap\uf3s plantio.This study compared the effects of container volume upon initial seedling growth of Cordia trichotoma (Vell.) Arrab. ex Steud and Jacaranda micranta Cham. 180 days after the planting. The plastic containers used were filled with commercial nursery substrate and displayed volumes of 55, 120, 180 and 300 cm3. No mortality was recorded among seedlings of all container sizes. There were no statistical differences in respect of height and stem diameter from seedlings cultivated in 120, 180 and 300 cm3 containers 180 days after the planting date

O uso de biossólido como fertilizante em eucalyptus

O desenvolvimento tecnológico e industrial, somado ao crescimento populacional, reflete graves problemas ambientais. A geração de resíduos urbanos é um exemplo representativo desse cenário. Os resíduos urbanos, mesmo após tratamento, resultam em água e sólidos cujo destino final adequado é preocupante. O biossólido apresenta, em sua composição, matéria orgânica — macro e micronutrientes — podendo ser aplicado como biofertilizante, auxiliando tanto na produção agroflorestal como na manutenção da fertilidade do solo. A utilização desse fertilizante orgânico em povoamentos florestais é admissível por não estarem voltados para a alimentação humana ou animal, diminuindo o risco de contaminação do homem. O projeto de pesquisa quantificará os efeitos da aplicação do biossólido no crescimento inicial de Eucalyptus citriodora Hook

Efeito da frequência da sangria em diferentes clones na produtividade de seringueira

The study evaluated the effect of tapping frequency on the productivity of rubber tree clones (PB235, IAN873, GT1 e RRIM600) planted in 1990 at Indianapolis-PR in a 8 x 4 m spacing. Treatments included tapping system in a half spiral every 3, 4 and 5 days. Data (g per tree per month) was collected from November, December and January of 2009/2010 and of 2010/2011 harvest seasons with ten repetitions. Results indicated that clone productivity was independent of tapping frequency.O trabalho avaliou o efeito da frequência de sangria na produtividade dos clones PB235, IAN873, GT1 e RRIM600 de seringueira no Município de Indianópolis-PR plantados em setembro de 1990 em espaçamento de 8 x 4 m. Os tratamentos constituíram dos sistemas de sangria em forma de meia espiral com frequências de 3, 4 e 5 dias . Os dados (g por árvore por mês) foram obtidos nos meses de novembro, dezembro e janeiro nas safras de 2009/2010 e de 2010/2011 com 10 repetições. Os resultados indicaram que a produtividade dos clones testados foi indiferente da frequência de sangria. &nbsp