Restoring Tropical Forests

Is planting clusters of trees a cost-effective and ecologically-sound strategy to restore tropical forest? Karen D. Holl(University of California, Santa Cruz) and Rakan A. Zahawi(University of Hawai'i, Manoa)

A major conservation challenge is how to restore the large areas of tropical forest that have been deforested. Over the past decade, there have been a growing number of commitments at the global, national and regional scale to restore forests because of their importance to conserve biodiversity, sequester carbon, reduce erosion, and provide goods and services to people. A common strategy to restore forests is to plant trees. But, an important question is how to plant trees in an ecologically-appropriate and cost-effective way.

Nearly two decades ago we started a multi-site study in southern Costa Rica to compare the efficacy of tropical forest restoration strategies, including natural forest regeneration (allowing the site to recover without planting trees), plantation-style tree planting, and applied nucleation (planting clusters of trees to help increase the rate of natural regeneration). In this module designed for upper-level college students with some background in ecology, we outline the obstacles to tropical forest restoration. We then compare the ecological and social outcomes of the three forest restoration strategies. Finally, we ask students to consider what ecological and social conditions are best suited to using an applied nucleation forest restoration strategy.

Rain-Forest-Data

https://www.learngala.com/cases/a3224235-cdc0-44fc-a98b-46735dfef6c9

Here are the files that you will need in order to get the app to work. If you need to edit the data here are some suggestions:

1)BoxwhiskerUI.R -Add text to before the dropdown (line 6)

2)Boxwhiskergenerate.R -Add how it looks for examples graphs(line 53-56 )

3)overviewUI.R -Able to add words and images to the front page *Under h1

4)UI.R -Change titles

Instructions

Here, you will have the opportunity to visualize the number of seeds of different categories falling (seed deposition) into the different restoration treatments using actual data. We collected the seeds in seed traps and then counted them twice monthly for 3.5 years(Werden et al. 2021○). The seeds fall into different categories. Successional stage: Early-successional species are better adapted to disturbed conditions and colonize early in the recovery process, whereas later-successional species tend to colonize more slowly and are found in mature tropical forest. Species labelled as “both” are found both early in succession and in more mature tropical forest. Growth form: We collected seeds of both trees and shrubs. Dispersal mode: Many trees and shrubs in tropical forests are dispersed by animals, whereas some are dispersed by wind. A few are dispersed by water or other methods but those aren’t included as separate categories here. Develop a hypothesis about how the seed deposition of a certain group of species varies across treatments. For example, how do you think that the number of seeds of wind-dispersed shrubs would differ across treatments and why? Then you can use the drop-down menus below to visualize the patterns of seed depositionJump to Edgenote across treatments. A quick hint that in general later-successional trees have more large, animal-dispersed seeds, whereas there are many shrubs and early-successional trees with small, animal-dispersed seeds. There are a few wind-dispersed species in each group, and the early successional wind-dispersed species produce a lot of seeds. If you select the “all” category it will include all species in that category (e.g. both animal- and wind-dispersed seeds).

Glossary

• Applied nucleation – planting clusters of trees dispersed throughout an area to enhance the rate of forest recovery. Natural regeneration (also referred to as passive restoration or natural forest regrowth) – An approach to restoration that relies on spontaneous increases in biota without direct reintroduction after the removal of degrading factors alone (Gann et al. 2019).

• Plantation – An area planted with trees, typically in rows and often for commercial purposes. The trees may be of one or multiple species.

• Reference forest – Reference forests are forests in the region that have never been fully logged but may have had selective logging or some human disturbance. They served as a reference model for how well the restoration treatments were recovering.

• Restoration – The process of assisting the recovery of an ecosystem that has been degraded, damaged, or destroyed (Gann et al. 2019). The target is usually a reference model informed by the historic ecosystem.

• Secondary forest – A forest that has regrown after logging, agriculture, or another major human disturbance.