Vlad Crisan - Academia.edu (original) (raw)

Papers by Vlad Crisan

Diversity, Mar 6, 2022

This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY

Forests, Jul 19, 2021

Soil Forming Factors and Processes from the Temperate Zone, Mar 23, 2017

Universitatea "Al. I. Cuza"-Iași Facultatea de Geografie și Geologie D e p a r t a m e n t u l d ... more Universitatea "Al. I. Cuza"-Iași Facultatea de Geografie și Geologie D e p a r t a m e n t u l d e G e o g r a fie Aca d emia Română F i l i al a di n I ași Colectivul de Geografie

Forests, Apr 17, 2018

More than a third of Romania's surface has low-productive soils, at the same time exposed to risk... more More than a third of Romania's surface has low-productive soils, at the same time exposed to risks of climatic phenomena and generating high economic loss. Afforestation with pine has been the most common solution for the recovery of sheet erosion. Many of the pines grown on such land have run down. This paper presents the results of the first dendroecological investigation of degraded lands in Romania, 80 years after the first ecological reconstruction. In this way, the effects of reconstruction were assessed, supporting the adoption of future solutions for the improvement and efficiency of recovered ecosystems. Reconstructed radial growth was set against rainfall, air temperature, and management history. A total of 330 black pine and Scots pine trees (Pinus sylvestris L. and Pinus nigra Arn.) of different ages and social positions from 11 stands of different densities were cored for retrospective tree-ring analysis. Scots pine has made better use of these sites, with a better growth rate than black pine especially in plantations with lower survival and on dominant trees. The dynamics of radial growth distinguish the two pine species, with Scots pine showing an accentuated juvenile growth spurt and bigger growth range. The growth decline is predominantly a maturation effect that begins when the tree is around 40 years old and seems to be irreversible. After this age, weak or moderated removal is not enough to revive growth. The contribution of climate (air temperature and rainfall) to the last radial increments in decline is 3-57% and is higher than in the previous decades. On moderately degraded land by farming and grazing, the mixture of Scots pine and black pine, rather than monocultures, proved to be a sustainable solution. Dendrochronological surveying of restored ecosystems allows development of management strategies, which becomes critically important in the circumstances of climate warming.

Forests, Apr 4, 2023

Research Journal of Agricultural Science, 2020

The present article describes the plants collected from Jepi Mountains area (Bucegi) and present ... more The present article describes the plants collected from Jepi Mountains area (Bucegi) and present in one of the most important Romanian herbarium-"Alexandru Beldie" Herbarium from "Marin Drăcea" National Institute for Research and Development in Forestry. The article presents the studied material, the number of vouchers with species harvested from this area as well as some characteristics of this great plant collection. The most important species collected from Jepi Mountains are also mentioned, with an analysis of their characteristics: the collection's creation period and the plant's harvesting periods. The plants collected from this area belong to 54 different genera. Most of them belong to Hieracium and Gentiana and were collected during the last century, starting with 1900 and ending in 1999. The found genera were systematized, with an emphasis on the most representative ones. Furthermore, the specialists that had an important contribution for the representation of Jepi Mountains within the herbarium are also mentioned and honored.

Revista de Chimie

State forests are analyzed periodically, once every 10 years. This includes an analysis of forest... more State forests are analyzed periodically, once every 10 years. This includes an analysis of forest soils. The present paperdescribes and interprets the chemical properties of forest soils from Bacau County focusing on the period 1983-2015. As such, 823 soil profiles and 2435 pedogenetic horizons were analysed taking into consideration the soil type, pH, humus content, nitrogen content, base saturation degree and the total cation exchange capacity. The most widespread types of soils are: eutriccambisol, luvisol, preluvisoland dystriccambisol. The dystriccambisols from Bacau County are strongly acid soils, while eutriccambisols and preluvisols are moderately acid. All forest soils from this area have a high cationic exchange capacity and are very well (dystriccambisol, eutriccambisol,luvisol) or well supplied (preluvisol, rendzina) with nitrogen. Knowing the chemical properties of soils is important for the analysis of stand variability and for adopting silvicultural methods adequate f...

Environmental Engineering and Management Journal, 2021

The present study investigates the influence of windthrows on the chemical and biological charact... more The present study investigates the influence of windthrows on the chemical and biological characteristics and respiration processes of forest soils from Romania. Three pure Norway spruce, common beech, and sessile oak stands were chosen together with control plots, where the forest and soils were not affected by windthrows. Soil samples were taken from two soil layers: 0-10 cm and 10-20 cm. Soil carbon dioxide fluxes or soil respiration was monitored at 20 randomly selected points for each sample surface. Soil temperature and soil water content were also measured at these points. Furthermore, the total number of heterotrophic bacteria and the total number of fungi were also measured. We found that abiotic factors lead to the modification of the chemical and biological properties of forest soils: soil pH was higher in the areas affected by windthrows, while humus and nitrogen quantities were lower in these areas. However, these changes were observed only in the first 10 cm of the soil profile. Underground microclimatic conditions were found to influence soil respiration, with higher respiration values observed in the surfaces affected by windthrows. In the Norway spruce and common beech stands, aerobe heterotroph bacteria and fungus were more abundant in soils that were not affected by windthrows because the uprooted trees remove top horizons of soils and the creation of leaf litter, roots and fungal hyphae, stops. In this situation, organic matter, in the soil, begins to decay.

SGEM International Multidisciplinary Scientific GeoConference EXPO Proceedings, 2020

Current Trends in Natural Sciences, 2021

Climatic modelling software was used in order to measure future changes in climatic conditions. T... more Climatic modelling software was used in order to measure future changes in climatic conditions. The software HYPE can realize prognosis for certain climatic factors responsible for causing extreme climatic phenomena in forest ecosystems. It was applied to study sessile oak forest ecosystems from Transylvania. Sample surfaces were installed, inventoried and followed by simulations of two future climatic scenarios. Two such scenarios were chosen, namely the climatic scenario in which the gas effect concentration will increase moderately (rcp-4.5) and the climatic scenario in which the gas effect concentration will be accentuated (rcp-8.5). The data was then processed and which led to an analysis of the way in which future climatic changes will affect forest ecosystems located in the studied area. After analyzing all three sessile oak stands, we can conclude that the Mediaș stand is the most vulnerable one to both climatic parameters. Future climatic scenarios are necessary for other s...

19th International Multidisciplinary Scientific GeoConference SGEM2019, Energy and Clean Technologies, 2019

Bulletin of University of Agricultural Sciences and Veterinary Medicine Cluj-Napoca: Horticulture, 2008

The climate represents:  climatic elements witch make the definition of the climatop;  radiant ... more The climate represents:  climatic elements witch make the definition of the climatop;  radiant energy: which represents the sunlight and the heat;  thermal regime elements;  the wet regime: evaporation and perspiration;  pluviometer regime  wind regime

Present Environment and Sustainable Development, 2021

A climatic modelling program was used in order to see the extent of changes in future climatic co... more A climatic modelling program was used in order to see the extent of changes in future climatic conditions. This can realize prognosis for certain climatic factors that cause extreme climatic phenomena concerning forest ecosystems. The program was applied for forest ecosystems comprised of Scots pine, installed and inventoried on sample surfaces from Transylvania. Simulations were then created within two future climatic scenarios. Two scenarios were chosen: the climatic scenario in which the increase of greenhouse gases would be moderate (rcp-4.5) and the climatic scenario in which the increase would be accentuated (rcp-8.5). The data was then processed, resulting in an analysis focused on the results of future climatic changes on forest ecosystems located in the studied area. By analyzing all three pine stands, we can conclude that the Lechinta stand is the most vulnerable one if the two climatic parameters change. It is necessary to verify and use future climatic scenarios for othe...

The realized investigations intended to evaluate the stand volume and current annual increment fo... more The realized investigations intended to evaluate the stand volume and current annual increment for the hybrid black poplar. The research was realized on the surface of 375 parcels, between 2010 and 2015. The following elements were evaluated: consistency, density, volume stand and current annual increment. Statistical analysis methods were used together with many numeric analysis methods. The approximation methods based on using neural networks are not very efficient. Furthermore, the interpolation method through analytical polynomial function with mixed terms used successfully in the systems characterized by significant changes in regard with certain state parameters, was used successfully in this case.

Bulletin of University of Agricultural Sciences and Veterinary Medicine Cluj-Napoca: Horticulture, 2021

The paper aims to present the plants collected from the former county of Turda and their characte... more The paper aims to present the plants collected from the former county of Turda and their characteristics, that are found in one of the most important herbariums in Romania the ‘Alexandru Beldie’ herbarium of the ‘Marin Drăcea’ National Institute for Research and Development in Forestry. The article presents the studied material, the number of vouchers with species harvested from this region, as well as some characteristics of this large collection of plants, such as the period when the collection was constituted and the periods of plant harvesting. For the studied herbarium, the genera were systematized, as the most representative genera were highlighted. Not only the most important species collected from the Turda County are indicated but, at the same time, the specialists who left their mark on the grassland representation in this area were also mentioned.

Journal of Forestry Research, 2020

The effects of different climatic conditions on growth and chemical composition of Betula pendula... more The effects of different climatic conditions on growth and chemical composition of Betula pendula in geographically different European regions, Lithuania and Romania, were compared. Birch species in the entire area have a wide natural distribution, but B. pendula is commercially more important in Lithuania than in Romania. Here we evaluated tree ring width, wood density and foliar chemical composition of mature birch trees in two European regions. Trees at the Lithuanian sites had greater radial growth and wood density with no clear changes in foliar chemistry than those at the Romanian sites. Mean wood density was 600–700 kg m−3 at Lithuanian and 350–450 kg m−3 at Romanian sites. Mean width of wood ring, earlywood and latewood for Lithuanian birch trees were several times higher than the means for Romanian birch trees. We hypothesized that the main differences in birch radial growth and wood density were due to the different climatic conditions in the studied regions. Ca, K and Mg concentrations were significantly higher and Fe and Mn were lower in the birch foliage at the Lithuanian sites compared those at the Romanian sites. Overall assessment of growth showed that silver birch cultivation is more appropriate for colder climate regions and that birch growth may change in the context of a warming climate.