Gap dynamics
Regardless of size, gaps allow an increase in light as well as changes in moisture and wind levels, leading to differences in microclimate conditions compared to those from below the closed canopy, which are generally cooler and more shaded.
Since gaps let in more light and create diverse microclimates, they provide the ideal location and conditions for rapid plant reproduction and growth.
In fact, most plant species in the tropics are dependent, at least in part, on gaps to complete their life cycles.
The next pathway is from tree remains, or any growth from bases or roots, and is common in small disturbance gaps.
[8] In high-latitude northern forests, position inside a gap can have a pronounced effect on resource levels (e.g., light availability) and microclimate conditions (e.g., soil temperature), especially along the north–south axis.
[5] Among the many factors affecting seedling establishment following canopy disturbance are parent tree proximity and abundance, seedbed substrate, presence of seed consumers and dispersers, and climatic and microclimatic variability.
[5] In a study near Chapleau, Ontario,[9][10] openings were created in 40-year-old aspen and monitored to determine their influence on outplanted white spruce seedling development.
Stomatal conductance in white spruce seedlings declined generally from more sheltered to more exposed environments, correlating best with increased vapor pressure deficit (VPD).
When major geological changes such as volcano eruptions or landslides occur, the current vegetation and soil may erode away leaving only rock.
Major holes or gaps in the forest ecosystem will take hundreds of years to regenerate from a rock base.
Finally, shade-tolerant species regain full canopy stature indefinitely until another major disturbance occurs.
[12] Secondary succession in the tropics begins with pioneer species, which are rapidly growing and include vines and shrubs.
Cecropias are also a major pioneering tree in the tropics and they are adapted to grow well where forest gaps are giving way to sunlight.
These successional phases do not have definite order or structure and because of the very high biodiversity in the tropics, there is a lot of competition for resources such as soil nutrients and sunlight.
Gaps create diverse microclimates, affecting light, moisture, and wind conditions (Brokaw 1985).
For example, exposure to edge effects increases a microclimate's light and wind intensity and decreases its moisture.
A study conducted on Barro Colorado Island in Panama showed that gaps had greater seedling establishment and higher sapling densities than control areas.
This explains the low recruitment rate per gap found in the experiment conducted in Barro Colorado Island.
This model helped estimate life expectancy, time of passage to various sizes, and age patterns of mortality.
