You Can Help Us Restore Osa’s Forests

Forest Restoration

Ecologically-driven Restoration

The world’s tropical forests are being degraded at an alarming rate, resulting in a huge loss of species diversity. In many areas, forests are slowly coming back through replanting trees to encourage forest recovery, turning the tide on deforestation.

However, Osa Conservation is moving beyond planting trees by taking a different approach to accelerate and increase the resilience of these new forests. Through strategic reforestation strategies, we are committed to:

  • Determining key areas for restoration & habitat migration
  • Increasing species diversity by making forests more complex
  • Sustaining predator-prey balances
  • Promoting our ideas through education and storytelling
  • Building public awareness about decisions that impact restoration efforts

In doing so, we hope to develop best practices towards fostering healthy tropical ecosystems and sharing solutions locally and internationally.


Our restoration team prepares saplings for planting.

Why are we doing this?

Bringing forests back following land abandonment is a complicated task. Often, the land has been used intensively (e.g. cattle grazing) and for such prolonged timeframes (>50 years) that primary forests that once existed might never return if left alone. Planted forests do not have a comparable degree of biodiversity or the structural complexity of an old growth forest. Birds have fewer trees good for nesting, epiphytes, plants growing on other plants, are absent and decaying deadwood is far from the necessary amount for ecosystem sustainability. In the Osa, large areas of land changed dramatically between 1976 and 2013, as seen below. Some wildlife populations have been driven to local extinction, as in the case of the harpy eagle and the giant anteater. In fact, many species associated with old growth primary forests are still missing from these traditionally restored ones. By focusing on restoring the missing biodiversity and the old-growth inter-species interactions, we will restore stability to the ecosystem.

Land cover change at Piro Biological Station in A) 1976 and B) 2013. Note the road dissecting the landscape, which in 1976 is surrounded by large swathes of introduced grassland to keep cattle, and only small patches of old growth forest outlined by the thin white lines. By 2013, much of this grassland had recovered back into tropical forest, which from above appears indistinguishable from the old-growth forest around it. However, when walking through, these the differences are stark, with many common species dominating the secondary growth and many of the rarer species still absent.

Land cover change at our biological station in A) 1976 and B) 2013. Note the road dissecting the landscape, which in 1976 is surrounded by grassland to keep cattle, and only small patches of old growth forest outlined by the thin white lines. By 2013, much of this grassland had recovered back into tropical forest although lacking key primary forest characteristics.


Our ecologically-driven forest restoration efforts aim to create biodiverse & ecologically self-sustaining forest ecosystems while testing methods for holistic restoration. Two of our main questions are:

  1. How can we regenerate old growth forests faster?
  2. How can we best restore critical ecological functions?


How will we do this?


Spider monkeys act as architects of the rainforest

1) Kick-starting forest recovery by adding biowaste, utilizing nutrient rich leaf litter latrines left by spider monkeys and thinning out dominant pioneer trees. Learn more about our spider monkey research research here.


2) Enhancing structural forest complexity by increasing seed rain from bats and birds, increasing small-scale, localized habitat availability, and improving pollination services.


With our passionate, hard-working land conservation staff along with students, volunteers and visitors, we have planted over 300,000 native trees representing over 50 different species, grown from hand-collected seeds raised in our on-site nursery designed to restore degraded habitats.


A newly planted Balsa sapling

Balsa Forest Restoration Experiment

Osa Conservation’s science team and researchers have developed experimental restoration plots to conduct long-term research for a better understanding of these important tropical rainforests and to create biodiverse and self-sustaining forest ecosystems.  In 2015, our first experimental plot tested the use of artificial roots to attract pollinating fruit-eating bats to deforested areas.  In 2017, we planted 14,007 saplings of 28 varieties of native species in 21 of the 40 plots.


Using 40 plots, with 4 distinct restoration techniques, we are analyzing different reforestation strategies, which serve as a model teaching tool for further understanding tropical ecological restoration.

The Osa lends itself as the ideal living laboratory in which to showcase human populations living alongside wild landscapes and incredible species diversity, while also acting as a think-tank for impactful tropical ecosystem rewilding and forest restoration.


“There can be no purpose more inspiring than to begin the age of restoration: reweaving the wondrous diversity of life that still surrounds us.” – O. Wilson