Development Rhythms of Pine Trees Introduced to the Zugdidi Botanical Garden

Abstract

Based on our observations it is obvious that growth rhythms and height (?) in various pines grown in the Botanical Garden in the period 2020-2021 are different.

One group of plants starts to grow either in the second half of March or April and finishes at different times. Cephalotaxus fortune, Taxus baccata, Cedrus deodara, Taxodium distichum, Sequoia sempervinens, and Cryptomeria japonica belong to this group. A second group starts its vegetation either in the second half of April or May. Podocarpus nageia, Abies alba Mill,Cunninghamia lanceolata,Cupressus lusitajnica mill, and Thuia occidentalis belong to this second group.

It is noteworthy that unfavorable climate conditions cause a significant delay in some pines’ development. Compared to 2020 Thuiaoccidentalis, Thujopsis dolabrata, and Podocarpus nageia Cupressus lusitajnica mill started their growth in 2021 with a 74-day, 69-day and 29-day delay respectively, whereas the rest of the plants had 6 to 18 –day delays.

Plant senescence and withering can be observed in some of the plants introduced to Zugdidi conditions. Cedrus deodara, Sequoia sempervinens, and Cryptomeria japonica have obvious symptoms of withering.

Based on our observations it is clear that withering is mostly connected to plant senescence in the introduced plants and starts from the age of 45-53. The factors that lead to plant senescence directly or indirectly facilitate withering as well. Moreover, the climate conditions in Springtime may be considered as one of the reasons for withering, namely a rise in air temperature, a drop in relative humidity, and negative effects of hot winds.

Observations made on the growth and development of pines introduced to the Zugdidi Botanical Garden illustrate that some of them are inclined towards the best growth and tend to be promising for green construction as well as in forestry.