Grafting to save the forest

Tropical forests (and all other forests) havesuffered enormous damage in recent decades.If the current rate of forest clearance in thetropics (estimated to be 150 000–250 000 km2per year)1,2 continues, they will disappear as amajor, large-scale ecosystem in many countriesduring the 21st century. As a result, a chain ofenvironmental problems, including increasedsoil erosion, damage to water resources and lossof a terrestrial carbon sink, will occur3.Approximately half of the tropical forests areclear-cut for shifting agriculture1, and, oncecleared, cannot be rescued. The rest of theforests are cut for timber supply and efforts canbe made to enable them to recover quickly.In mature fruit orchards of tropical,subtropical and temperate origin, grafting ispracticed routinely when a better variety isdesired4. Accordingly, we propose that at leastsome of the felled trees in the tropical andtemperate forests should be grafted using theirown material. Grafted trees resume growthquickly because the sprouts enjoy the welldevelopedroot system of the mature trees.Such forest management techniques mightgenerate significant benefits: ensuring geneticcontinuity; enable clonal improvement (incommercial forests); preserving the mycorrhizaand other soil biota; keeping a huge quantityof root biomass (on average 26% of shootmass5) alive and active; preventing soilerosion; shortening the period of time forforest regeneration; increasing sustainability;reducing CO2 emissions to the atmosphere andincreasing its incorporation into biomass;and reducing the dependency on nurseryoperations, which are costly, and in manydeveloping countries, the technology forhigh quality forest seedling production doesnot exist.In countries with low labor costs (whichincludes most tropical countries), grafting canbe practiced on a large scale. A team ofgrafters might follow the harvesting team andgraft the cut trees with shoots from the canopyof the same tree or with selected material. Inaddition, in specific commercial forests, eliteclones can be grafted to retain desiredqualities, or individual tree species can begrafted, such as Taxus trees cut to producetaxol. In this way, selected grafting in cutforests could provide an opportunity tomanipulate the landscape and to formfragmented forests or open-park forests. Thegrafting must be done while the cambium isactive – spring and early summer in thetemperate regions, and most of the year in thetropics6. The establishment of this simplemethod in tropical and temperate forests couldhelp to change the current rate of decline anddamage to global forests. Legal, administrativeand management measures should be coordinatedto facilitate the application of thismethod.