In recent years, deforestation process is accelerating with global warming and climate change. Biodiversity is deteriorating and important genetic resources are at risk of extinction. In order to prevent these changes that take place in nature, the idea of conserving natural resources and forests is at the forefront. Together with the very high cultural and scientific value, Turkey has many natural riches, many of which are protected and should be protected. Among them, monumental trees provide scientific, psychological, cultural, aesthetic and touristic functions. Monumental trees contain important information about the different events of the past. Besides, they are the sources that are utilized in the planning stages of forest resources by functioning as a gene pool in terms of species. In this study, Genc-Güner method was used and five monumental trees were determined in Gaziantep region. The crown diameter, bark thickness, breast height diameter and total height of the trees were measured. With the help of increment core samples, age estimation were carried out. According to National Standard of Monumental Trees (TS 13137), two of five trees was registered as a monumental tree because of its characteristics. With the estimated age of 500 years, 25 and 26 m height, 220 and 226 cm breast height diameter, these trees are Platanus orientalis L. species. They are of natural, cultural and aesthetic value.

Photorespiration and drought-induced stomatal closure are two important physiological constraints that reduce carbon assimilation and productivity in C₃ forest trees under Mediterranean climatic conditions. Türkiye’s two dominant commercial pine species, Pinus brutia Ten. (Calabrian pine) and Pinus nigra J.F. Arnold subsp. pallasiana (Anatolian black pine), together cover approximately 8.15 million hectares. This study integrated published gas-exchange measurements, radiation-use efficiency estimates from MODIS, official forest inventory data, and dendrochronological growth records into a counterfactual accounting framework and propagated parameter uncertainty by Monte Carlo simulation (N = 40,000 draws). The two constraints jointly reduced weighted-mean net primary productivity (NPP) from a radiation-limited potential of 5.61 to an actual 3.46 Mg C ha⁻¹ yr⁻¹, a reduction of 37.9% (95% CI 32.2–43.4%). Decomposition shows that 47.7% of this loss is the obligate metabolic cost of C₃ carboxylation, which no silvicultural intervention can address, while 52.3%—20.1 of the 37.9 percentage points—is drought-attributable. Nationally, the deficit corresponds to 64.3 Mt CO₂ yr⁻¹ of forgone sequestration (47.8–81.2) and 34.4 Mm³ yr⁻¹ of forgone stemwood-volume equivalent (24.9–44.5), of which approximately 20.6 Mm³ would be merchantable, giving an annual economic deficit of USD 3.37 billion (2.40–6.48). Filtering the drought-attributable component for eligible area, recovery efficiency, additionality, leakage, and permanence yields approximately 1.0 Mt CO₂ yr⁻¹ of potentially issuable credits, fewer than two per cent of the headline figure. Eco-physiological suppression of this magnitude is currently invisible in national forest carbon accounting, and its recognition bears directly on dynamic baseline design and on the credibility of offsets generated from Mediterranean conifer forests.

Water availability is the primary environmental factor limiting plant establishment in arid and semi-arid ecosystems, and increasing drought-stress due to climate change is making forest restoration efforts in the Mediterranean basin increasingly critical. The Eastern Mediterranean region of Türkiye, particularly Kahramanmaraş Province, is characterized by increasingly severe drought stress resulting from low natural precipitation and rising temperatures under global warming. This study comparatively evaluates the ecophysiological responses of Ailanthus altissima (Mill.) Swingle and Crataegus orientalis Pall. ex M. Bieb., under adequate irrigation and drought-stress conditions. To determine plant water status, pre-dawn and midday leaf water potentials were measured, and leaf gas exchange was characterized by measuring net photosynthesis (A), stomatal conductance (gs), and transpiration rate (E); water-use efficiency (WUE) was then derived from these parameters as the ratio of net photosynthesis to transpiration (A/E). Both species sustained positive net photosynthesis under drought, although at rates significantly below those of the well-watered controls in the driest months, and both attained higher WUE than the controls in most months, with marked seasonal variation. However, significant differences in physiological adaptation strategies emerged between the species. Ailanthus altissima exhibited a water-saving strategy, restricting stomatal conductance to maintain a stable leaf water status, whereas Crataegus orientalis adopted a water-spending strategy, sustaining high leaf gas exchange while tolerating pronounced tissue dehydration. Modeling results, supported by spatial drought stress indices, have shown that both species have high adaptation potential in arid and semi-arid rehabilitation areas. The findings reveal that ecophysiological characteristics play a critical role in the selection of drought-tolerant woody species and provide a scientific basis for sustainable forest restoration under climate change.

Water availability is the primary environmental factor limiting plant settlement in arid and semi-arid ecosystems, and increasing drought stress due to climate change is making forest restoration efforts in the Mediterranean basin increasingly critical. The Eastern Mediterranean region of Turkey, particularly Kahramanmaraş Province, is characterized by increasingly severe drought stress resulting from low natural precipitation and rising temperatures under global warming. This study comparatively evaluates the ecophysiological responses of Ailanthus altissima (Mill.) Swingle and Crataegus orientalis Pall. ex M. Bieb. under adequate irrigation and drought-stress conditions. To determine plant water status, pre-dawn and midday leaf water potentials were measured; water use efficiency (WUE) was calculated using net photosynthesis rate, stomatal conductance, and transpiration parameters. Both species were able to maintain photosynthetic activity under drought conditions and showed higher WUE values compared to control conditions. However, significant differences in physiological adaptation strategies emerged between the species. Ailanthus altissima exhibited a water-spending strategy with rapid physiological adjustment, while Crataegus orientalis adopted a conservative water-saving strategy through pronounced stomatal regulation. Modeling results, supported by spatial drought stress indices, have shown that both species have high adaptation potential in arid and semi-arid rehabilitation areas. The findings reveal that ecophysiological characteristics play a critical role in the selection of drought-tolerant woody species and provide a scientific basis for sustainable forest restoration under climate change.

In this study, the wood and stem structures of selected woody species employed in afforestation practices in the Central Anatolia Region, one of the arid and semi-arid zones of Turkey, were examined under natural conditions. The species investigated included black locust (Robinia pseudoacacia L.), Arabian almond (Amygdalus arabica L.), and fourwing saltbush (Atriplex canescens (Pursh) Nutt.). Their anatomical attributes conferring resistance to drought stress were assessed. Wood samples obtained from these species were prepared as permanent slides, and both xylem anatomical features and fiber morphological characteristics were analyzed. In conclusion, due to its possession of numerous and small-sized tracheae, its short and thick fiber structure, and its high abundance of bordered pits, Atriplex canescens can be prioritized for use in this and similar areas. The findings indicate that Robinia pseudoacacia and Amygdalus arabica are ecologically capable of tolerating drought and may therefore be utilized in afforestation programs in comparable environments. Moreover, their fiber structure and the abundance of bordered pits suggest a capacity for rapid adaptation to such conditions. Collectively, these results demonstrate the ability of these species, which naturally occur in arid regions, to withstand adverse environmental factors, and highlight their potential for use in future rehabilitation and plantation projects due to their favorable resilience traits.

Ulmaceae familyasından bir tür olan Celtis australis L.(Adi çitlembik), ülkemizdeki yabani meyveli türlerden biri olup, genelde küçük gruplar halinde ya da tek yayılış gösterir. Bu türün Kahramanmaraş ili Andırın yöresinde doğal meşcere kuruluşu bulunmaktadır. Bu çalışmada, Kahramanmaraş Andırın yöresindeki Celtis australis L. (Adi çitlembik)’in küme, grup ve küçük grup şeklinde bulunan doğal iki meşceresi tespit edilerek, toplanan kaliteli tohumlar, değişik rakımlardaki üç fidanlıkta üretilmiş, bir yaşında elde edilen fidanlarda gelişimlerinin tespiti için boy ve kök boğazı çapı ölçümleri yapılmıştır. Fidan üretimleri, Kahramanmaraş Orman Bölge Müdürlüğü sınırlarındaki Antakya Serinyol Fidanlığı (50 metre), Gaziantep ili İslahiye fidanlığı (400 metre) ve Kahramanmaraş Tekir Fidanlığı (1000 metre)’nda yapılmıştır. Fidanlık çalışmalarında tohumlarda çimlenme oranının %95 ve üzerinde olduğu görülmüş ve 1 yaşındaki fidanların (50 adet) fizyolojik gelişimleri ayrı ayrı yapılan ölçümlerle Antakya Serinyol Fidanlığı’nda (boy:41,3±4,2 cm, kök boğazı çapı:2,1±0,2mm), Gaziantep İslahiye Fidanlığı’nda (boy:42,3±3,9 cm, kök boğazı çapı:2,1±0,3 mm) ve Kahramanmaraş Tekir Fidanlığı’nda (boy:34,8±2,8 cm, kök boğazı çapı:4±0,6 mm) belirlenmiştir. Üretilen fidanlarda büyüme gerçekleştikten sonra vejetasyon dönemini takip eden ilk dört ay içerisinde (Mayıs, Haziran, Temmuz ve Ağustos) gün ortası yaprak su potansiyelleri ölçülerek, su stresine dayanıklılıkları tespit edilmiştir. Yetiştirilen fidanlarda en yüksek gün ortası yaprak su potansiyeli değerleri Serinyol Fidanlığı’nda Ağustos ayında (-2,14 MPa (Ψ)) elde edilmiştir. Stres koşulları dikkate alındığında su stresine en çok maruz kalan fidanlar Serinyol Fidanlığı’nda üretilen fidanlar olmuştur. Bu bilgiler ışığında, farklı fidanlıklarda üretilen türe ait fidanların kurak bölgelerde yetiştirilmesi ve plantasyonu, türün yetiştirilmesi ve gen kaynaklarının belirlenerek korunmasında öneli rol oynamaktadır.