The Effects of Stem Length and Diameter on Cuttings

Abstract

When we open newtowns or roads in hilly areas, revegetation as slope protection is necessary after cut and fill. Reforestation is better than covering with grass from the viewpoint of resisting erosion and restoring the native landscape. However, we can never plant big trees on steep slopes, and it takes long times for young tree growth. So stem cuttings seems to be suitable, if it would be possible. In the previous articles, we made it clear that several broad-leaved evergreen trees showed a considerable rooting by the treatment with β3-Indolebutyric acid (IBA) 2000ppm solution, even with 16-18cm stem girth. And comparatively dry condition brought better results than shading or frequent watering.The additional experimental research was conducted with different size of Camellia japonica, Ilex crenata and Quercus glauca, in 1988.
The results were as follows: Every stem height (25, 50 and 100cm above the earth) cuttings of Camellia japonica sprouted shoots at 95.8 % by early July (after 118 days since beginning). In the case Ilex crenata, the shorter stem showed the better sprouting such as 100.0, 58.3 and 33.3% respectively, and this brought similar results on life or death by summer end. Quercus glauca had only a few sprouting (24.3%) even with 50cm height, and all died with 100 and 150cm.
In late November (after 253 days since beginning), the rooting results were observed. Camellia japonica and Ilex crenata showed respectively 70.8%, 87.5% rooting ratio with 25cm stem height. Half the number of both species developed roots also with 50cm stem height, and moreover, the former species showed nearly same rooting ratio with 100cm stem height. However, Quercus glauca brought poor results such as 27.0% even with 50cm stem height. In the previous experiment, we observed good rooting of Quercus glauca with 30cm stem height. Therefore, it is judged that we should control the stem height within 25 or 30cm when we expect satisfactory results in cuttings. Incidentally, Quercus glauca, Camellia japonica and Ilex crenata showed an ability to develop sufficient roots even with such wide stem diameter as 10, 8 and 7cm respectively.