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Five years of sap flow records to estimate the effect of transplanting on Magnolia grandiflora water uptake

Takeuchi, S., Iida, S., Matsuda, A.
Acta horticulturae 2018 no.1222 pp. 195-200
Magnolia grandiflora, canopy, cutting, heat, leaf area, leaves, photosynthesis, pruning, root systems, roots, sap, sap flow, stem elongation, tree growth, trees, water uptake, xylem
Very few studies have revealed the effects of transplanting on the flow of tree sap. Using the heat ratio method, we measured the heat pulse velocity in the trunks of Magnolia grandiflora L. for five years after transplanting and detected an increase in the sap flow for four years. This trend was supported by measurement of sap flux using the thermal dissipation method over two years. Focusing on the radial distribution of the sap flow in the trunk revealed that the increase of the outer sap flow after transplanting was considerably greater than that of the inner sap flow. On the other hand, we observed an increase in the sap flow conducting area of 8 mm in width over four years. The fact that leaf area of the evergreen crown just before the transplanting was almost equal to the total area of fallen leaves after four years clearly indicated the increase of the total leaf area. We also observed an obvious expansion in roots using soil surveying methods. The measured increase in the sap flow was consistent with tree growth. Our results showed that conductivities of xylem before and after transplanting were similar, although the canopy and root system were damaged significantly by pruning and cutting of roots to construct a root ball. Thus we can conclude that photosynthetic products were distributed to allow the recovery of the damaged foliage and the root system rather than for stem growth.