Guide to Writing a Research Paper

“Stand Dynamics of a Coast Mangrove Forest in Puerto Rico”
In 1998 we re-measured 10 mangrove plots that had been established in 1984 in Jobos Bay National Estuarine Reserve. We found three mangrove species in the overstory and two in the understory. Rizophora mangle had the highest total tree density (live and dead trees) and total basal area. Laguncularia racemosa had the highest living basal area represented and about a third of the live tree density of Rizophora. Laguncularia was the most dominant species in terms of basal area exhibited positive changes in basal area, tree density and ingrowth. Avicennia germinans had a few trees in the overstory, a few seddlings in the understory, and no dead trees. Ingrowth trees were growing two to fourteen times in diameter faster than trees tagged in 1984. We found more dead trees than live ones, due mostly to Rizophora. Annual mortality rate ranged from 8.7 to 15.9 percent. High salinity, normal stand thinning, and hurricane disturbance are the likely causes of the observed stand changes.

“The Effects of Fire Disturbance on Stand Conditions Within the Central Cascades Forest Ecosystem”
The forested landscape within and surrounding the H.J Andrews Long Term Ecological Research (LTER) Area is influenced by long term successional processes punctuated by both human-induced and natural disturbances. The historic disturbance patterns in these forests include such factors as wind, disease, and both low intensity and stand replacement fires. During the last 100+ years, timber harvesting has become the major disturbance factor influencing these ecosystems. The historic fire return interval for any stand depends on many factors, including slope, aspect, proximity to water or other natural fire breaks. Disturbances from timber management practices, such as clear cutting, selective cutting, pre-commercial thinning, commercial thinning, and prescribed burning have different impacts on these forested ecosystems than natural disturbance processes. Understanding how historic fires influence successional processes across the landscape is important to the understanding of how to direct forest management activities and retain the ecological values of different forest conditions. In addition to their role in other ecological processes, Late Successional Reserves (LSR’s) provide unique habitat values for old-growth dependent wildlife.
This study will look at two stands located just outside the H.J. Andrews LTER in the Blue River Watershed on the Willamette National Forest in the central Cascades region in Oregon. The two study sites have similar slope, aspect, and elevation and are located less than 1km from one another. This study looked at the effects historic high-intensity fires on specific stand conditions including: Stand Density, and the Relative Densities, Relative Dominances, and Importance Values for each tree species. Tree core samples were collected in each study area and yielded evidence that the “Second Growth” stand had a major disturbance (most likely a natural fire) approximately 150 years ago. The fire history for this stand was also confirmed using visual evidence such as: “cat faced” or fire-scarred trees, large diameter dead and downed wood, and charcoal on the bark of few remaining old trees. While a few 500+ year old Douglas-Fir (Pseudotsuga menziesii) survived the event, much of the stand was dominated by 100-150 year old Western Hemlock (Tsuga heterophilla). These trees formed a closed canopy condition resulting in a very open understory. In contrast, the “Old Growth” stand studied had no visual evidence of fire and a multi-layered canopy with numerous gaps between the oldest trees that allowed for sunlight to penetrate and promote the growth of a dense understory layer of vine maple, rhododendron, and young trees. The lack of charcoal or fire scars and presence of large diameter (500+ year old) fire-sensitive species such as Western Hemlock and Western Red Cedar were indicative of the lack of high intensity fire in the stand. This study was initiated from a basic ecological question of what differences, if any, can be observed in the species composition, density, and frequency between a stand that is in recent recovery from a fire event compared with a stand that has no history of a fire event. A preliminary Hypothesis proposed is that the “Old Growth” stand would demonstrate greater species diversity than the “Second Growth” stand, but perhaps a smaller overall basal area of tree coverage.