The growth characteristics of Juniperus excelsa M. Bieb. in the greenhouse conditions of the Southern coast of the Crimea

Federal State Funded Institution of Science “The Labour Red Banner Order Nikitsky Botanical Gardens - National Scientific Center of the RAS”, Nikita, Yalta, 298648, Russia.

^* Corresponding author: a.v.pashtetskii@gmail.com

Abstract

The dependence of the growth intensity of Juniperus excelsa M. Bieb on some environmental factors in the greenhouse conditions of the Southern Coast of the Crimea was studied. Vegetation and trunk diameter growth (d,%) started after March 15. There are two growth peaks: the first growth peak (15.03.–27.07.) led to an increase in d,% by 7.12% (0.053% per day) – with a slowdown in growth (28.04 –27.05) and (13.07 – 25.07) associated with a decrease in air temperature. The second – (12.09 – 18.11) led to an increase in d,% by 5.06% (0.075% per day), while also slowing growth at this time (05.11.–14.11.) was observed. After the second phase of active growth (14.11), there is an access to the growth plateau with the resumption of the growing season only in March next year. During the studied vegetation period (2019), the increase in trunk diameter d,% was 12.18% or 1.89 mm. Optimal conditions of maxima and boundaries of optimal regions for the first growth peak: d%=f(I,Ta) – Ta=22–28°C, I=500–800 mkmol/m²s, for d,%=f(I,Da) – Da=1.8–2.3 kPa, I=500–800 mkmol/m²s. For the second growth peak: d%=f(I,Ta) – Ta=22–26°C, I=400–750 mkmol/m²s, for d,%=f(I, Da) – Da =0.3–1.2 kPa, I=400–750 mkmol/m²s.