The invention discloses a cultivation method which combines a small tree into a tree with large
trunk diameter and comprises following steps: A. selecting 10 to 30 small trees with DBH of 3 to 10 centimeters, keeping the coiled root and the
trunk of each small tree close to each other correspondingly, and
combing and fixing the small trees into a big tree
embryo; B. putting the big tree
embryo vertically into a tree pit and filling the soil back, consolidating the soil and watering until the soil is permeant, surrounding the periphery of the
trunk of the big tree
embryo with a cylinder body, filling the soil into the cylinder body, and watering for preserving
moisture; C. removing the cylinder body and the soil from the periphery of the trunk, keeping consistent fertilization with dilute
fertilizer,
pruning deadwood or verminous branches and leading the small trees to grow into a combined body which is a tree with big trunk
diameter. The invention has no requirements to the shape of small trees, does not need to remove
fibril, can implement the combination with tree barks, has convenient maintenance and easy tree survival and does not need curing in plastic tents; furthermore, the invention can shorten the survival and growth period of the big tree by adding the soil into the cylinder body, and the cultivation cost is very low. The method is simple and applicable for extensive
tree species, has
high survival rate, quick growth and shorter cultivation period, and acquires the big tree with a
solid core after growing up which has long natural survival time; the method is especially applicable for the projects of city
virescence and gardening landscape.