Medžiu būkles stebesena ir vertinimas kauno miesto aplinkoje

Santrauka

Analizuojami 2002 ir 2008 metais Kaune atliktos medžiu miesto gatviu želdiniuose, skveruose, parkuose ir miško parkuose būkles stebesenos ir vertinimo rezultatai. 69‐iuose Kauno aplinkos stebesenos objektuose buvo ivertinta 769 apskaitos medžiu būkle pagal indikacinius morfologinius rodiklius (laju defoliacija, lapijos arba spygliu dechromacija, derejima ir sausu šaku kieki lajoje). Didžiausia vidutine laju defoliacija nustatyta paprastuju kaštonu (Aesculus hippocastanum L.) – 45,3±2,5 %, mažalapiu liepu (Tilia cordata Mill.) – 29,3±3,9 % ir uosialapiu klevu (Acer negundo L.) – 28,2±3,1 %. Ypač dideles paprastuju kaštonu laju defoliacijos pagrindine priežastis – ne oro tarša, o keršosios kaštonines kandeles (Cameraria ohridella Deschka & Dimic) pažeidimai. Apskaitos medžiu dechromacija palyginti nedidele. Palyginus 2008 ir 2002 metu medžiu būkles stebesenos duomenis, akivaizdus medžiu, išskyrus paprastuosius kaštonus (Aesculus hippocastanum L.), būkles pagerejimas. Nustatyti medžiu morfologiniu rodikliu skirtumai miesto mikrorajonuose. Taikant ArcGIS programa atliktas miesto teritorijos zonavimas, pagal vidutine medžiu laju defoliacija išskiriant 5 aplinkos būkles zonas, indikuojančias aplinkos palankuma medžiams augti: medžiams augti labai palanki (laju defoliacija ≤15 %); palanki (16–25 %); vidutiniškai palanki (26–35 %); nepalanki (36–45 %) ir labai nepalanki (defoliacija >45 %).

Abstract

The paper presents the results of monitoring the changes of selected parameters in different tree species carried out on 69 observation plots in the city of Kaunas in 2002 and in 2008. The morphological parameters (crown defoliation, foliage discolouration, fruiting rate and amount of dry branches) of 769 sampled trees were evaluated. The investigation indicated that trees growing closer to streets had greater defoliation compared to trees growing in city wooded areas or parks far from the streets. The largest average crown defoliation was observed for Aesculus hippocastanum L. – 45.3±2.5%, Tilia cordata Mill. – 29.3±3.9% and Acer negundo L. – 28.2±3.1%. The main reason of large crown defoliation and worse health condition of Aesculus hippocastanum was air pollution and the cankerous impact of Cameraria ohridella Deschka & Dimic. It is established that large tree foliage dechromation is not widespread in the city of Kaunas. The comparison of monitoring data of 2008 and 2002 indicated the trend of improvement in the health condition of all the tree species, except Aesculus hippocastanum L. The differences in the morphological parameters for the sampled trees in different city regions were estimated. Using an ArcGIS program a map was created with 5 zones for crown defoliation in trees for the city of Kaunas: (defoliation ≤15%) a very favourable zone; (defoliation 16–25%) a favourable zone; (defoliation 26–35%) a moderately favourable zone; (defoliation 36–45%) an unfavourable zone; (defoliation >45%) a very unfavourable for tree growth zone. These zones indicated the degree of suitability of the city environment to tree growth.

Reikšminiai žodžiai:

• miesto medžiu būkle
• stebesena
• morfologiniai rodikliai
• tarša
• miesto zonos

Keywords:

• urban trees
• monitoring
• assessment of health condition
• morphological parameters
• environmental pollution
• city zones.