Tree planting has become the most visible environmental action, and evaluations of planting projects have found survival rates and ecological outcomes that are frequently poor.
Planting is not restoring
A forest is a system of many species, soil biota, hydrology, structure and processes.
Planting trees establishes one component.
Which is why a monoculture plantation is not a restored forest, and why counting trees planted measures effort rather than outcome.
Survival
Trees planted are not trees grown.
Studies assessing planting projects years later have found survival rates varying enormously, with a substantial proportion of projects showing poor results.
Which means headline planting figures overstate outcomes considerably, and follow-up monitoring is what distinguishes serious projects.
Causes of failure include inappropriate species, poor site matching, planting at the wrong time, no aftercare, and browsing.
The wrong place
Planting trees on habitats that were not forest.
Native grasslands, savannas and peatlands are ancient ecosystems with their own biodiversity, and afforesting them destroys it.
Which has occurred at scale under restoration programmes, and it has been criticised strongly by ecologists working on those systems.
Peatland afforestation is particularly counterproductive, since draining peat to plant trees releases more carbon than the trees sequester.
Natural regeneration
Frequently cheaper, faster and more effective than planting where seed sources are nearby.
Which means the first question should be whether the site will regenerate on its own if pressures are removed.
Assisted natural regeneration — protecting from grazing and fire, controlling competing vegetation — costs far less than planting and produces more diverse results.
It is less visible, which is part of why planting attracts more funding.
Species selection
Native species matched to the site support far more biodiversity than fast-growing exotics.
Which conflicts with the incentive to demonstrate rapid growth, and fast-growing exotics dominate many planting schemes.
Diverse plantings are more resilient to disease and to climate variation than single-species ones.
The carbon claims
Trees sequester carbon, and the accounting is more complex than the headline suggests.
Sequestration takes decades, while emissions occur now.
Permanence is uncertain, since fire, disease and land use change can release it.
Soil carbon effects can be negative depending on the site.
Which is why offset schemes based on planting have attracted substantial scrutiny, with investigations finding a considerable proportion of credits did not represent real additional sequestration.
Land rights
Large-scale planting requires land, and projects have displaced existing users.
Which has occurred in several documented cases, and it is why land tenure and consultation are now central to credible project standards.
What works
Protecting existing forest, which is dramatically more effective than replacing it — old growth cannot be recreated on any relevant timescale.
Natural regeneration where seed sources allow.
Native species matched to site, planted with aftercare and monitored for years.
Community involvement and benefit, which determines whether the trees remain.
And measuring outcomes rather than inputs, which very few schemes actually do.
Old growth
Cannot be restored on any human timescale.
Structural features — large old trees, standing dead wood, complex canopy, accumulated deadwood on the floor — take centuries.
Which means protecting remaining old growth is categorically more valuable than any amount of planting, and the two are frequently traded against each other in policy.
Soil and fungi
Forest soil hosts fungal networks that trees depend on, and these develop slowly.
Which is why trees planted into degraded soil frequently struggle, and why inoculation with appropriate fungi improves establishment in some contexts.
Soil carbon in mature forest is substantial and is disturbed by planting operations.
Deer and grazing
In many regions, browsing pressure prevents regeneration entirely.
Which means fencing or population management is a precondition for restoration, and planting without it wastes the effort.
This is the single most common cause of failure in temperate regions with high deer densities.
Measuring restoration properly
Survival rates after several years rather than trees planted.
Species diversity and structural complexity rather than canopy cover alone.
Return of dependent species — birds, invertebrates, fungi — which indicates whether the system is functioning.
And soil condition, which underlies everything else.
Which requires monitoring over decades that few projects fund.
Agroforestry
Integrating trees into agricultural systems rather than separating the two.
Which delivers some ecological benefit on land that remains productive, and it addresses the land competition objection directly.
Evidence on yields is mixed by system and generally favourable for soil, water and diversification.
Choosing where to donate
Organisations that report survival rates, use native species and monitor for years are distinguishable from those reporting only trees planted.
Which is a straightforward question to ask, and the answer is informative.
Which distinguishes organisations doing restoration from those doing planting, and the two are marketed identically.
Local organisations working in one landscape over decades generally outperform international schemes operating at scale, since they know the site and remain accountable for the outcome.