Å UMARSKI LIST 9-10/1967

sem u slučajevima kada je na oštećenom mestu došlo do ulančavanja sekundarnih
negativnih uticaja abiotičke i biotičke prirode.
f) Brzina zatvaranja pukotina, bez obzira na njenu veličinu, u mnogome
zavisi od kvaliteta, odnosno ukupne fiziološke snage i aktivnosti ozleđene biljke.
Kod jačih sadnica ovaj proces teče znatno brže, jer su zarasle pukotine dužine
117 i 134 cm nađene već polovinom juna.
Kao interesantno ostaje i dalje da se vrše osmatranja o ponašanju sadnica
oštećenih od mrazopucina. Naročito je važno utvrditi brzinu zarašćivanja ncsraslih
mrazopucina, kvalitet drveta na oštećenom mestu, otpornost na vetrolome
i snegolome, otpornost na uticaj parazita. Od posebnog je interesa pratiti
ponašanje oštećenih sadnica i oštećenih mesta na uticaj niskih temperatura
u budućnosti.
Navedeni podaci o pojavi pucanja stabala topole ovde su dati samo u onom
obimu koji se tiče odnosa sa ekstremnim niskim temperaturama. Međutim, koliko
je ova pojava u vezi i sa nekim drugim činiocima a koji se verovatno nalaze
u tehnologiji gajenja i fiziološko-anatomskim odlikama na ovaj način uzgajanih
biljaka, ostaje da se utvrdi na osnovu izučavanja oštećenih topolika,
kao i putem eksperimentalnih ogleda koji su u toku.
INJURIES FROM LOW TEMPERATURES TO PLANTS OF EURAMERICAN
POPLARS CULTIVATED» IN PLANTATIONS
Summary
During ihe winter of 1963'64 there occurred a fissuring of stems in a great number
of plants in 2-year-old Poplar plantations over larger areas of Eastern Slavonia,
Baranja and Bačka.
This phenomenon was recorded in all localities where in 1962 new Poplar stands
were established irrespective of the various different conditions of the soil, the regime
of underground and flood waters, and the degree of applied agrotechnical and
silvicultural measures. The numb:r of fissured stems on 1200 ha of these plan'ations
in individual localities amounted to 13.0—28.4% in the clone 1-214, and 11.2—12Va
in the clone »robusta«.
The number of splits occurring most frequently on the southern and southwestern
sides is varying in individual plants. It ranges from 1 to 8, averaging 1.96,
while the length of the split is from 2 to 178 cm., averaging 32.46 cm.
As the mentioned phenomenon was not recorded earlier — although Poplar
stands in Baranja have been established since 1956 after similar or identical silvicultural
techniques — the splitting of stems is correlated to the detrimental influence
of the extreme high and low daily air temperatures characteristic of the late November
and December of 1963.
Because this phenomenon represents a serious problem in intensively managed
plantations for Pcplarwood production, complex investigations were aiming at determining
the true causative agent of this phenomenon.
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