Considering the importance of the pine woods in the Adriatic costal zone, like a natural defence against the attack of the storm waves tending to produce the regression of the shoreline, this study is a preliminary attempt for a more detailed investigation that will try to correlate geological, lithological, climatological and paleobotanical parameters to obtain a better knowledge of the evolutional trend of the different environments in different times of the North Italian Adriatic coastal zone

Marabini, Francesco

Mertzanis, A.

PUblication MAnagement

CHINA-ITALY BILATERAL SYMPOSIUM ON THE COASTAL ZONE AND CONTINENTAL SHELF EVOLUTION TREND 
October 5-8, 2010 - Bologna (Italy) 120 
THE PINE WOODS ALONG THE SEA SHORELINE: A NATURAL 
DEFENCE OF THE NORTH ITALIAN ADRIATIC COASTAL ZONE 
 
F. Marabini1 and Α. Mertzanis2 
 
1
 National Research Council, ISMAR, 101 P. Gobetti str., 40129, Bologna (BO), Italy, 
franco.marabini@bo.ismar.cnr.it 
2
 Technological Educational Institute of Lamia, Department of Forestry and 
Management of Natural Environment, 36100, Karpenisi, Greece, amertzanis@teilam.gr  
 
 
Abstract 
Considering the importance of the pine woods in the Adriatic costal zone, like a 
natural defence against the attack of the storm waves tending to produce the 
regression of the shoreline, this study is a preliminary attempt for a more detailed 
investigation that will try to correlate geological, lithological, climatological and 
paleobotanical parameters to obtain a better knowledge of the evolutional trend of 
the different environments in different times of the North Italian Adriatic coastal 
zone.  
 
1. INTRODUCTION   
The northern Adriatic coastal zone is today affected by a continue 
regression of the shoreline. Going from North to South, one first meets the thin 
Venetian littoral with the lagoon at its back; the Po river delta follows, developing 
into the sea. From this point to the Gabicce promontory, south of Ravenna town, a 
continuous shallow sandy littoral with the Po plain at its back extends. All this 
coastal area is very fragile because it is given by a large zone under the sea level, 
with marshland and small lagoons, separated from the sea by a thin sand dunes 
line, fixed by woods: pinewoods in the Ravenna coastal zone and pine and Quercus 
ilex near the Po river delta (Figures 1 & 2). 
Today the massive occupation of the coastal zone by man activity, for 
economic – touristy purposes, produces, the distruction of the sand dunes and of 
the pinewoods with negative effect on the coastal zone equilibrium. 
 
2. METHODOLOGY  
The history of the vegetation is connected with the evolutional history of 
the northern Adriatic coastal zone. During the Pleistocene Wurm glacial period 
CHINA-ITALY BILATERAL SYMPOSIUM ON THE COASTAL ZONE AND CONTINENTAL SHELF EVOLUTION TREND 
October 5-8, 2010 - Bologna (Italy) 121
about 20,000 years B.P. the Adriatic Sea level was from 90 to 130 m. lower than 
the present and the coastline was about 300 km further south, leaving an emerged 
plain in the northern part of the Adriatic region. The Late Pleistocene continental 
complex is formed mainly by interbedded layers of clay, sand and peat; the 
continental origin of which is confirmed by the textural characteristics of the 
sediment layers and their palaeontological contents. Important studies by Bortolami 
et. al.[2] on pollen obtained from samples from different cores in the Lagoon of 
Venice and the Lower Po Valley provided important information on the subsidence 
and climatic fluctuations in the northern Adriatic region. Their study briefly 
indicates: 
 
 
Fig. 1 - Scheme of natural zonation in the coastal zone of the Adriatic lowlands – 
Vegetation profile in the Venice Lagoon [1] 
 
Fig. 2 - Scheme of natural zonation in the coastal zone of the Adriatic lowlands – 
Vegetation profile in the Pineta of Ravenna [1] 
 
- following a continuous subsidence and sedimentation rate of about 1.3 mm/year 
from before 40,000 to 22,000 years B.P., the least glacial peak, the sedimentation 
rate increased drastically to at last 5 mm/year, probably caused by an accelerated 
downward movement of the basin, i.e. an isostatic effect, 
CHINA-ITALY BILATERAL SYMPOSIUM ON THE COASTAL ZONE AND CONTINENTAL SHELF EVOLUTION TREND 
October 5-8, 2010 - Bologna (Italy) 122 
- a sedimentation gap ends the Pleistocene (18,000-7,000 years B.P.), and 
- an episode of emergence that corresponds to the compaction and 
overconsolidation of a clay layer considered as an indicator of the Holocene / 
Pleistocene boundary 
 
Bortolami et. al.[2] also found that the Pleistocene peat samples consist of 
the same type of Cyperaceae peat throughout the stratigraphic column indicating 
that the growth conditions, i.e. hydrologic situation, must have been approximately 
the same during each period of peat development. Furthermore the authors suggest 
that a good correlation between age and depth of the sediments implies that the 
sedimentation was strictly related to the subsidence of  the basin floor. Palynologic 
analyses gave important indications on the climatic variations and on the related 
vegetational phases for the time span between 40,000 and 18,000 years B.P. 
A study by Bortolami et. al.[2] on pollen from peat samples from the 
northern Adriatic basin gave C14 date of 39,000 B.P. and indicates the following 
five climatic phases: 
- a Gramineae steppe period with Juniperus, Artemisia, Ephedra and some 
scattered pine trees indicating a cold and dry climate, 
- sixty percent increase in tree pollen percentage such as oak forest elements, 
traces of beech (Fagus), fir (Abies), pines (Pinus), birch (Betula) and spruce 
(Picea), between 38,000 to 34,000 years B.P., could be attributed to warmer and 
more humid conditions with some climatic changes within the same period, 
- with the occurrence of steppe vegetation such as Gramineae, Chenopodiaceae 
and few pines at 33,000 years B.P., a change to cold climate could be recorded, 
- between 32,000 and 23,000 years B.P., 50% increase in pine pollen with fairly 
high value for Gramineae, Artemisia, Ephedra and Juniperus,indicates an open 
pine forest in the steppe with a dry climate. But between 31,000 and 29,000 years 
B.P., more humid condition were developed as indicated by the presence of  oak 
(Quercus), elm (Ulnus) and poplar (Populus), and 
- a steppe type vegetation with up to 70% Gramineae, Artemisia, Juniperus and 
Chenopodiaceae characterized the 22,000-18,000 years B.P., period with very 
dry and cold climate. 
 
The authors also report a striking resemblance, despite the great distance, 
when they correlate the vegetation phases of the Venetian region with those from 
CHINA-ITALY BILATERAL SYMPOSIUM ON THE COASTAL ZONE AND CONTINENTAL SHELF EVOLUTION TREND 
October 5-8, 2010 - Bologna (Italy) 123
other locations in the Mediterranean area. 
 
3. RESULTS - DISCUSSION   
3.1 Pleistocene emergence 
The Pleistocene period ends with a phase of no sedimentation (18,000-
7,000 years B.P.) in the Venetian lagoon. In fact no Pleistocene continental 
deposits younger than 17,800 years B.P., have been recorded in the region. During 
the final phase of the Pleistocene period the shallow argillaceous deposits are 
drained, compacted and oxidized to form the overconsolidated levels known in the 
Venetian lagoon as “caranto” and representative of the Holocene / Pleistocene 
limit. The lack of sedimentation corresponds to the beginning of the declaciation, 
the Flandrian transgression. 
 
3.2 The Flandrian transgression  
With the climate improvement that started about 17,000 years B.P., and 
reached its maximum about 6,000 years B.P., the sea level began to rise and the 
coastline moved progressively northwards over the Adriatic palaeoplain until it 
reached approximately the present position about 6,000 years B.P. That period was 
characterized by an intense and prolonged alluvial phase. Wave motion and sea 
current reworked and dispersed the fluvial sediments carried to the sea and formed 
the sandy littoral bar which delineated the primordial northern Adriatic shoreline 
(Figures 3 & 4). 
In addition to the described long-term climatic variations during the 
geological times, we have record of recent times short-term climatic fluctuations. 
At the end of the last century, Brukner [3] published a study pointing out a 
sequence of climatic fluctuations based on the comparison of meteorological data 
which resulted similar, for the same period, in different parts of the Northern 
Hemisphere. Using geological, geomorphological, glaciological, palaeobotanical, 
archaeological and historical investigations, it has been possible to reconstruct the 
sequence of climatic variations with accuracy for the historical times. 
For the last 3,000 years, five cold and humid periods have been recognized 
that had a great impact on the Mediterranean basin. The periods were: 1400-1300 
years B.C.; 900-300 years B.C.; 400-750 years A.D.; 1150-1300 years A.D.; 1550-
CHINA-ITALY BILATERAL SYMPOSIUM ON THE COASTAL ZONE AND CONTINENTAL SHELF EVOLUTION TREND 
October 5-8, 2010 - Bologna (Italy) 124 
1850 years A.D. 
The cold/wet periods were alternated with warm/dry periods and they have 
been well identified by the dendrochronological curves. Within these “large scale” 
periods, small climatic fluctuations of 10-35 years continued with cold/wet and 
warm/dry cycles up to present time. The influence of these climatic changes on the 
environmental evolutional trend is obvious. 
Man’s intervention greatly modified the natural evolution not only of the 
Venice Lagoon but also, though not so drastic, of the Upper Adriatic coast. 
Witnesses of the combined man intervention and climate fluctuations are the 
vegetation changes with time. When the Romans arrived in the Ravenna area they 
found extensive forests and swamps. The landscape modification started with the 
land reclamation for agriculture purposes by the Romans. Still at the end of the 
Roman period the city Ravenna was surrounded by swamps and pinewoods of 
Pinus pinaster and Pinus pinea, and Quercus ilex. These forests were kept as 
natural barriers to control the frequent floods. 
The evolution of the Po River Delta and the mild climate near the sea 
favoured the formation of the coastal dunes of the Mesola Pinewood 1200-1000 
years B.P. The wood consists of three types of vegetation: (a) one type mainly of 
Quercus ilex that indicates a humid Mediterranean climate around 1200-1000 years 
A.D.; (b) a mesophile type of Quercus robus and Carpinus betulus and (c) an 
igrophile type with Fraxinus oxycrapa. During the following centuries an intense 
forest cutting and marshland reclamation firstly for agriculture use and more 
recently for industrial activities were witnessed.. 
 
3.3 Present time 
At present while Mesola Pinewoods and other woodlands along the coast 
still exist, in the Venetian lagoon none of the original woods remain and only 
vegetation typical of a marshland environment can be found. 
With the disappearance of the coastal woodlands, a natural barrier against 
the erosion by the sea has also disappeared facilitating a coastline regression [4]. It 
must be also mentioned, that the strong winter sea-storms of the past 50 years 
along with cold/wet climate during the 1950-1970, period further damaged and 
depleted the forests along the Upper Adriatic coasts. 
CHINA-ITALY BILATERAL SYMPOSIUM ON THE COASTAL ZONE AND CONTINENTAL SHELF EVOLUTION TREND 
October 5-8, 2010 - Bologna (Italy) 125
 
 
Fig. 3 Fig. 4 
Fig. 3 & 4 -The Upper Adriatic Palaeoplain during the Wurmian glaciation (Fig. 3). The Upper 
Map indicates areas below sea level (Fig. 4) [1] 
 
 
It is therefore, concluded that while for the Venice Lagoon only man-made 
barriers could be effective against sea-storms, we should perhaps consider an 
afforestation program along the Upper Adriatic coast, to protect the natural 
ambience with species of plants, such as Olive from Bohemia, more resistant to 
cold winter weather and salty moisture from the sea. 
 
4. CONCLUSIONS   
The importance of the presence of pinewoods is evident in the northern 
littoral of the Adriatic coastal zone where the trees permit the stability of the 
ancient coastal dune line against the storm waves action and against the modest, 
but continuous, sea level increasing from the end of the last glacial period. From 
the Gabicce promontory to South, the coastal zone is given by a cliff, with a 
narrow gravely beach at the sea. Even in this case the presence of woods is 
important, even if different, considering the northern Adriatic littoral, because it 
permits to face and contrast the destroing frequence of the coastal landslides, with 
regression of the cliff, during the cold/wet climatic variations with large abundance 
of rain causing landslides in the “flysh” of the cliffs. 
CHINA-ITALY BILATERAL SYMPOSIUM ON THE COASTAL ZONE AND CONTINENTAL SHELF EVOLUTION TREND 
October 5-8, 2010 - Bologna (Italy) 126 
Acknowledgments 
 
This research is supported by the E.C. LIFE – environment project N. LIFE 03 
ENV/UK/000611 
 
REFERENCES 
Sestini G. (1989). Sestini G., “Implications of  climatic changes for the Po Delta 
and Venice Lagoon. UNEP. Athens. 108 pp.  
Bortolami G.C., Fontes J.Ch., Markgraf V. & Saliege J.F. (1977). “Land sea and 
climate in the northern Adriatic region during late Pleistocene and Holocene”, 
Palaeogeography, Palaeoclimatology, Palaeoecology. 21: 139-156.  
Bruckner E. (1890). “Klimaschwankungen seit 1700 nebest Bemerkungen uber die 
Klimaschwankungen der Diluvializeit”, Geographisce Abbandlungen. B4 (2) 153-
184. 
Marabini F., & Veggiani A. (1991). “Evolutional trend of the coastal zone and 
influence of the climatic fluctuations. The Second International Symposium on 
Coastal Ocean Space Utilization. Long Beach, CA (U.S.A). 


The Pine Woods along the sea shoreline: a natural defence of the north italian Adriatic coastal zone.

http://puma.isti.cnr.it/rmydownload.php?filename=cnr.ismar/cnr.ismar.bo/2010-A2-006/2010-A2-006.pdf

The Pine Woods along the sea shoreline: a natural defence of the north italian Adriatic coastal zone.

Abstract

Similar works

Full text

Available Versions

PUblication MAnagement