The Botanical Review

, Volume 59, Issue 4, pp 251–272 | Cite as

Tree invasion and establishment in old fields at Hutcheson Memorial Forest

  • Randall W. Myster


In this review I present results from pattern analysis and field experiments in New Jersey, United States concerning tree invasion and establishment in old fields. Hutcheson Memorial Forest Center (HMF) is the New Jersey study site and a logical choice to anchor a review of this topic. HMF contains the longest and largest old field permanent plot study in the USA including extensive data concerning tree invasion and establishment. HMF has also been the site of considerable old field tree experimental research. In addition, I review other investigations of old field tree invasion and establishment of the eastern deciduous biome and contrast them with HMF. I identify critical questions concerning tree invasion and establishment, indicate what progress has been made towards answering these questions and propose future experimentation. I also synthesize results into a conceptual model and investigate the relative importance of seed and seedling processes in determining tree dynamics in old fields.

The idea of a possibility or “window” for tree invasion and establishment and its variation form the basis for this review. For example, the temporal variation of windows is reflected in tree establishment patterns at HMF because wind- and bird-dispersed species invaded one year after cessation of cultivation while mammal-dispersed species were not present until year 12. Although analysis of size classes of individual HMF trees imply that windows close quickly, studies are of too short duration to tell definitely. Spatial variation in invasion and establishment pattern includes exponential decline in seed and stem density with distance from forest edge which deteriorates with time as the old field becomes more structurally complex. Additional spatial heterogeneity occurs when seeds and seedlings of bird-dispersed species clump which conversely becomes more pronounced with time. Many of these HMF patterns are seen in other eastern United States old field sites.

When reviewing field experiments from my site and others, I focus on the spatial and temporal variation and the difference between species in the effect of processes on tree seeds and seedlings. I do this because this variation relates directly to the dynamic nature of windows whose quantification is necessary for modeling. Combining my pattern analysis with a survey of variation in seed and seedling mortality caused by different successional processes in old fields, I conclude that seed dispersal, conditions necessary for seed germination and seed and seedling predation are the critical processes controlling and constraining tree invasion and establishment in old fields. Competition and indirect effects of litter and the environment, which modify how these processes affect tree dynamics, are also important. Therefore, processes involving the interaction of species with the environment and with other species form the principal filters on and limitations to tree invasion and establishment and not the non-interactive life-history traits of individual tree species such as growth rate or longevity. The interaction of pattern and process and the affect of many of these processes on old field community structure are also discussed.


En este estudio presento los resultados de análisis de patrones y experimentos de campo en New Jersey, Estados Unidos relacionados con la invasión y establecimiento de árboles en campos abandonados. Hutcheson Memorial Forest Center (HMF) en New Jersey es una alternativa lógica para desarrollar este tópico. HMF contiene el area de estudios relacionados con el monitoreo de vegetación en campos abandondos más grande y de más larga historia. HMF también ha sido el sitio de investigatión de arboles en campos abandonados por décadas. También estudie otras investigaciones de invasión y establecimiento de arboles en campos abandonados en un bioma forestal del este y los comparé con los de HMF. Identifico preguntas críticas sobre la invasión y establecimiento de árboles, indico cual es el progreso hecho en contestarlas y propongo experimentos futuros. Finalmente, yo sintetizo los resultados en un modelo conceptual e investigo el papel que juegan los procesos a nivel de semillas y plántulas en la dinámica de arboles en los campos abandonados.

Las ideas de la oportunidad de una invasión y establecimiento de árboles y su tiempo de invasión forman la base para este estudio. Por ejemplo, la variedad del tiempo de invasión se refleja en los patrones de establecimiento de los arboles en HMF. Porque las especies de arboles dispersadas por el viento y aves invadieron un ano despues de la cosecha mientras que las especies dispersadas por mamiferos invadieron despues 12 anos. Aunque el análisis de los tamanos de los árboles en HMF implica que la oportunidad de invasión no dura mucho, es to no se puede con cluir ya que los estudios fueron de muy corta duración. La variación espacial en el patrón de invasión y establecimiento de los arboles tiene una reductión exponencial en la densidad de semillas y tallos de donde termina el bosque. Esta reducción se desvanece según la estructura del campo abandonado se complica can el tiempo. En contraste, un patrón espacial que se hace mas aparente con el tiempo es el amontonamiento de semillas y plántulas dispersas por aves. Muchos de estos patrones son observados en otros campos abandonados en el este de Estados Unidos.

Cuando reviso los experimentos en el campo de HMF y de otros lugares, enfoco el efecto que tienen la variedad en tiempo y espacio de la invasión y la diferencia entre las especies de árboles en los proceso a nivel de semillas y plántulas. Esta variedad se relaciona directamente con la naturaleza dinámica de las oportunidades de invasión cuya cuantificación es necesaria para hacer el modelo. Combiné mi análisis de los patrones con un estudio de variación en la mortalidad de las semillas y plántulas causadas por diferentes procesos sucesivos en campos abandonados. Concluí que la dispersión de semillas, las condiciones críticas para la germination de semillas y el consumo de semillas y plántulas son los procesos críticos que controlan la invasión y establecimiento de árboles en los campos abandonados. La competencia entre plantas y los efectos indirectes del ambiente y de la capa de vegetación muerta en el suelo, modifican cómo los procesos de dispersión, germinación y consumo afectan la dinámica de los árboles. Por lo tanto, son las interacciones de las especies con el ambiente u otras especies las que controlan la invasión y establecimiento de árboles y no las características de las diferentes especies tales como el incremento en crecimiento o longetividad. Las interacciones de patrones y procesos con la estructura de la comunidad en campos abandonados estan discutidos también.


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© The New York Botanical Garden 1993

Authors and Affiliations

  • Randall W. Myster
    • 1
  1. 1.Terrestrial Ecology DivisionUniversity of Puerto RicoSan JuanUSA

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