Estrutura populacional e incremento corrente anual de casca-de-anta (Drimys brasiliensis Miers - Winteraceae) em Caçador, Santa Catarina, Brasil / Population structure and annual increment in "casca-de-anta" (Drimys brasiliensis Miers - Winteraceae) from Caçador Municipality, Santa Catarina State, Brazil

Drimys brasiliensis Miers, conhecida como cataia ou casca-de-anta, é árvore nativa da Mata Atlântica e as cascas tem sido utilizadas medicinalmente a partir da exploração de plantas em populações naturais. Este trabalho teve como objetivo estudar a demografia de duas populações naturais de D. brasiliensis, (1) Reserva Genética Florestal de Caçador (RGFC) e (2) Floresta Nacional de Caçador (FLONA), ambas no município de Caçador (SC), visando fundamentar estratégias de exploração sustentável e conservação deste recurso florestal não-madeireiro. A maior luminosidade no sub-bosque existente na FLONA atuou positivamente na espécie, aumentado a capacidade de incremento em diâmetro à altura do peito (DAP), altura (H) e área basal (AB), além de antecipar a reprodução em plantas de menor porte. A análise do padrão espacial das plantas reprodutivas na RGFC mostrou padrão agregado, e na FLONA até a distância de 25 metros. Esse comportamento indicou que a espécie apresenta potencial de manejo em florestas secundárias, formação sucessional em que se encontra a maioria dos remanescentes de Mata Atlântica, além de indicar potencial para cultivo em sistemas agroflorestais.

Known as "cataia" or "casca-de-anta", Drimys brasiliensis Miers is a tree native to the Atlantic Forest and its barks have been medicinally used by exploring natural populations. The present work aimed to study the demography of two D. brasiliensis natural populations, (1) Caçador Forest Genetic Reserve (RGFC) and(2) Caçador National Forest (FLONA), both located in Caçador Municipality, Santa Catarina State, Brazil, in order to establish strategies for sustainable exploration and conservation of such non-timber forest resource. The higher luminosity in FLONA understory was beneficial to the species by increasing their increment capability regarding diameter at breast height (DBH), height (H) and basal area (BA), and made the reproduction in smaller plants earlier. The spatial analysis of reproductive plants in RGFC had an aggregate pattern, whereas in FLONA until 25m distance was detected. Such results indicated that this species presents potential for management in secondary forests, the successional formation where the major Atlantic Forest remnants are found, as well as potential for cultivation in agroforestry systems.

Dinámica del daño foliar en plántulas de Drimys granadensis (Winteraceae) y Clusia multiflora (Clusiaceae) en el bosque altoandino de la Cordillera Oriental colombiana

Leaf damage dynamics of Drimys granadensis (Winteraceae) and Clusia multiflora (Clusiaceae) seedlings in the High-Andean Forest. Because of their slow growth, shade-tolerant species remain exposed to foliar damage long before reproductive age. Foliar damage can be controlled through synchronous leaf production and specialized phytochemical strategies. in this study, the dynamics of foliar damage in different cohorts of seedlings were evaluated to determine if the High-Andean species, Clusia multiflora (Clusiaceae) and Drimys granadensis (Winteraceae) appeal to the synchronous leaf production for controlling the herbivory and pathogenical damage, and to establish the possible relations between the healthy state, growth and mortality of seedlings. Since a recently-emerged seedling could not supply the physiological costs of specialized strategies, we expected the highest synchronous leaf production in the youngest individuals, and differences between cohorts in foliar damage. Four variables were measured to evaluate the health state along time, in three cohorts of seedlings: Proportion of predated leaves (Pp), proportion of healthy leaves (Ps), proportion of leaves with symptoms of disease or punctual damage (Pe) and growing (% increment of height). Both species showed significant differences between periods in the proportion of healthy leaves, but there was not an effect of time-cohort interaction, therefore synchronic production of leaves was not a strategy more used for any particular cohort. Foliar damage oscillated along time, fact that can be explained by the pulses of leaf production. However, this strategy had little efficiency to control the pathogen attack. in general, the unified behavior of all variables was affected by cohort, time, species an all the different interactions. Association between growing and foliar damage were conditioned by climate. The highest mortality ocurred during the dry season, and one fourth of the D. granadensis deaths were caused by the joint action of herbivory and drought. Results suggest that in spite of the synchronous leaf production in all cohorts, this strategy quickly loses the efficiency for controlling foliar damage, because the means of Ps were below of 0.25 at the end of the monitoring period. The differences between species in the dynamics of health state should explain partially their coexistence in the High-Andean forest. Rev. Biol. Trop. 56 (3): 1087-1100. Epub 2008 September 30.

Además de las estrategias fitoquímicas especializadas, las plantas pueden usar la producción sincrónica de hojas como un método de saciado de patógenos y herbívoros. Con el fin de determinar si las especies del bosque altoandino colombiano Clusia multiflora (Clusiaceae) y Drimys granadensis (Winteraceae) recurren a la producción sincrónica de hojas para controlar los efectos de la herbivoría y el ataque microbiano, y establecer que relación existe entre el estado de salud, el crecimiento y la mortalidad de plántulas, se evaluó la dinámica del daño foliar sobre diferentes cohortes. Dado que una plántula tolerante a la sombra recientemente emergida no puede suplir los costos fisiológicos de una estrategia especializada, se esperaba una alta sincronía en la producción de hojas en las plántulas más jóvenes, y diferencias en el daño foliar entre cohortes. Se midieron cuatro variables que evaluaban el estado de salud a lo largo del tiempo, en tres cohortes de plántulas: Proporción de hojas predadas, proporción de hojas sanas, proporción de hojas enfermas o con daño puntual y crecimiento. Ambas especies mostraron diferencias significativas entre épocas, en la proporción de hojas sanas; pero no hubo un efecto de la interacción tiempo-cohorte, por lo tanto la producción sincrónica de hojas no fue una estrategia más usada por alguna cohorte en particular. El daño foliar osciló a través del tiempo, lo cual puede ser explicado por los pulsos en la producción de hojas. Sin embargo, ésta estrategia tuvo poca eficiencia para controlar el ataque por patógenos. En general, el comportamiento unificado de todas las variables fue afectado por la cohorte, el tiempo, la especie y todas las diferentes interacciones. La relación entre crecimiento y daño foliar fue condicionado por el clima. La mayor mortalidad se dio durante la estación seca, y un cuarto de las muertes en D. granadensis fueron causadas por la acción conjunta de herbivoría y sequía. Los resultados sugieren que a pesar de la producción sincrónica de hojas en todas las cohortes, fue poca la eficiencia para controlar el daño foliar, ya que las medias de Ps estuvieron por debajo de 0.25 al final del seguimiento. Las diferencias en la dinámica del estado de salud entre especies podrían explicar parcialmente la coexistencia en el bosque altoandino.