Final answer:
Pioneer species are fast-growing and quick to reproduce, initiating soil development for late-successional species, which are larger trees growing slowly and forming a stable climax community. In the field, size, growth rate, root robustness, and shade tolerance are indicators of a tree's successional status.
Step-by-step explanation:
Common differences between pioneer species and late-successional species in the tropics are reflected in their adaptations to different environmental conditions during ecological succession. Pioneer species can colonize landscapes devoid of soil and initiate the process of succession. They tend to grow and reproduce quickly to take over the landscape and improve the soil quality for future species. Late-successional species, on the other hand, are generally larger trees that appear later in succession once the soil has become sufficiently enriched by the pioneers. These larger trees are more successful at competing for resources and tend to form a more stable climax community.
In the field, to make an educated guess as to which group a small tree belonged to, you could look for characteristics such as the tree's size, growth rate, the robustness of its root system, and its tolerance to shade. Pioneer species typically are smaller, grow rapidly, and have less extensive root systems. They are also often sun-loving, with lower tolerance for shade. Conversely, late-successional species would likely be larger trees that grow more slowly and have extensive root systems that allow them to outcompete the pioneer species and thrive in the shade created by their canopy.