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Dryocosmus kuriphilus is a new chestnut pest that is causing a serious problem worldwide. This gall wasp causes severe infestations of Italian Castanea sativa stands, which lowers their productivity. The most effective method for controlling gall wasp infestations is to introduce the parasitoid, Torymus sinensis, although experience shows that it can be 6-18 years before it is effective in reducing the infestation to acceptable levels. From a silvicultural point of view, it is important to reduce the damage as rapidly as possible to maintain plant vigour and fruit production, thereby avoiding chestnut stand degradation and abandonment before biological control is effective. This study analyzed the damage caused by Dryocosmus kuriphilus during normal plant development and detected differences in plant susceptibility, irrespective of genetic factors. Data were collected from a young Castanea sativa coppice stand in Tuscany (Italy) where damage was evaluated during the 2010 growing season. The study consisted of two phases: (1) classification of the damages caused by galls; and (2) studying the galls and damage distribution effects on different vigour chestnut sprouts to determine whether there were preferred oviposition sites or different degrees of susceptibility to gall wasp attack depending on a plant's physiological state. The D. kuriphilus damage classification scale was based on two factors: damage position (the vegetative organ attacked) and damage effect (abnormal organ development caused by galls). This classification included damage types that had not been previously described in literature. The statistical analysis identified differences in damage susceptibility in terms of: axis (stem or branches), plant organs (shoots, leaves, or buds), position of the attacked node (high or low region of the axis), and sprout vigour. Information on the D. kuriphilus damage distribution and its effect on plants with different levels vigour can be used to develop suitable cultural practices that could reduce the negative impact of this insect on fruit and wood production.

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Peat, a non-sustainable resource, is still predominately used in forest nurseries. Coconut coir might provide an alternative, renewable, and reliable growing media but few studies have evaluated this media type in forest nurseries. We assessed the influence of pure coir, in combination with various fertilization regimes, on the growth and physiology of three ecologically diverse Quercus species seedlings (Q. robur, Q. pubescens, and Q. ilex) during nursery cultivation. Seedlings were grown using peat and pure coir in combination with three fertilization treatments (standard, K-enriched, and P-enriched). Data were collected for: (1) growth and physiological traits; (2) detailed above- and below-ground morphological traits by destructive analysis; and (3) NPK content in leaves, shoot and roots, and in the growing media, following cultivation. Peat and coir in combination with the various fertilization treatments affected above- and below-ground morphology and, to a lesser extent, the physiological traits of Quercus seedlings. Large effects of the substrate occurred for most morphological variables, with peat being more effective than coir in all studied species. Fertilization also produced significant differences. The effect of K-enriched fertilization on plant growth was clear across the three species and the two growing media. P-enriched fertilization in peat was the only combination that promoted a higher amount of this element in the tissues at the end of cultivation. Despite their smaller size, seedlings produced in coir were compatible with standard Quercus forest stocktype size, and showed a proportionally higher root system development and fibrosity. Our results suggest that coir can be used as an alternative substrate to grow Quercus species seedlings, and that fertilization can offset coir deficiencies in chemical properties. As several functional traits drive planting performance under varying environmental conditions. according to the Target Plant Concept, coir might thus serve as an acceptable material for seedling cultivation in some cases.

Logging operations using heavy machinery effect changes in soil characteristics due to compaction; such conditions can negatively influence seedling development. In stands managed on the basis of close‐to‐nature silviculture or continuous cover forestry, successful establishment of natural regeneration after logging is important to ensure the proper functioning of a forest ecosystem, to promote soil recovery, and to prevent and mitigate land degradation processes (such as soil erosion, mudflow, waterlogging, and landslides) related to soil compaction and rutting. This work aimed to assess the early response of Quercus robur seedlings to soil compaction during the first 1.5 months after germination. The study was carried out in a controlled environment using 8 L containers filled with natural alluvial soil. Three levels of soil compaction were applied in a laboratory using a compression‐testing machine placed on the top surface of the soil in the containers. The morphological traits of the seedling shoot and root systems were analysed to compare 3 compaction levels. There were significant differences in seedling traits among the treatments, and they indicated that increasing levels of compaction reduced early seedling growth after emergence. Compaction had a larger impact on the root system, particularly the development at depth (root system depth, and main root length), compared with the shoot system. Our results suggest that compaction affects seedling root system growth following the first growth stages after germination; thus, compaction represents an additional critical factor for seedling establishment, particularly in environments where early growth is crucial for overcoming the dry season.

Container size and shape impacts biomass allocation of nursery seedlings. Effects of different pot types on shoot and root growth and biomass allocation were evaluated in nursery cultivation of Quercus robur L. and Juglans regia L. We compared two containers currently used in Italian forest nurseries (ISSA-pot®; Plastecnic®) and two alternative types (Superoots Air-pot®; Tubex®); different pot sizes were also included: two for ISSA-pot and Plastecnic; four for Air-pot. Seedlings were evaluated during 1-year nursery growth and biomass allocation was determined on a sub-sample at the end of the growing season. For both species, seedlings grown in larger containers generally grew more and containers >4.5 l produced the largest seedlings. Root biomass was >50% of total biomass in all containers with the tap-root comprising the major root system component. Air pruning in the Air-pots inhibited seedling growth of both species in narrow deep pots, while in bigger sizes (wide and deep) it produced positive responses, especially for walnut. Container configuration differentially affected the studied species: shoot and root system development of walnut seedlings was more limited by pot diameter than depth. Q. robur had improved shoot and root system development when grown in Tubex.

Sasso Fratino Nature Reserve (National Park of Casentino Forests, northern Apennines) is a quite rare example of natural Apennine forest. The Reserve was established in 1959, aiming to protect a forest, although not a virgin one, low-intensively disturbed in the past by comparison with other neighbouring stands. Causes of such a low disturbance are the very limited accessibility of the area due to the very steep slopes characterising the site morphology, as well as historical features. The forest is a pure beech stand from 1250 m a.s.l. upwards, below this altitude is a mixed beech and silver fir forest. The study focuses on the understanding of the processes driving the evolution of the forest in the absence of human activities. To achieve this goal, 9 permanent, long-term research plots were established at different altitudes, in order to investigate on forest dynamics and regeneration processes. Simplified (single-layer) stand structures are more frequent where canopy gaps are absent. Two-layered structures are the result of the occurrence of canopy gaps, which allow the settlement, and subsequently the establishment, of a lower regeneration layer. Where the gap dimensions allow canopy closure, this kind of structure persists. When the gaps are quite large, the regeneration layer reaches the top layer and the structure stand tends, once more, toward a single-layer. Multilayered structures are extremely rare at plot level and become evident only at a wider scale. Our surveys indicate also a high variability of tree diameter distribution patterns in the forest stands. Such variability could be strictly related to the heterogeneity of site characteristics as well as to the effects of disturbance factors (both natural and anthropic). Concerning altitude, we observed an increase both of site index (dominant height) and species diversity in the regeneration layer, moving from higher (1500 m) to lower (900 m) altitudes. As a whole, our observations show that the dynamics of forest vegetation in the reserve is mostly affected by the interruption of tree canopy continuity. This implies substantial local variations of PAR in space and in time, which determine favourable ecological conditions for: (a) survival and growth of beech seedlings, or release of advanced beech regeneration; and (b) release of advanced silver fir regeneration (fir, more shade tolerant than beech, regenerates mainly in locations and conditions where the broadleaf saplings cannot survive for lack of light). The knowledge of the mechanisms of vegetation dynamics in the Reserve can be used to form the basis of close-to-nature silvicultural choices in similar stands in order to increase functionality and stability. Periodical monitoring of RNI will allow the investigation of the evolutionary trends of the forest stands