Reference ecosystems are a valuable tool for restoration and management efforts in degraded ecosystems. Longleaf pine (Pinus palustris), a pyrophytic southeastern U.S. ecosystem, have declined precipitously in extent since European settlement. Pine mortality and growth patterns were examined in a 15-year re-measurement study in two old-growth stands. Both stands experienced postire mortality and short-lived decreases in basal area. Distance to nearest neighbor had a significant effect on mortality of small (<10 cm DBH) pine. To better approximate reference conditions, saplings of five co-occurring hardwood species were destructively measured for bark accumulation and taper using bark and wood thickness. Significant species differences were detected in bark:wood ratio (P<0.001), with no difference in wood diameter. Blackjack oak (Quercus marilandica) had a bark:wood ratio 3x the closest species and steeper slopes of bark accumulation, suggesting that it is a fireapted species. These results will inform reference conditions for critical regional pine restoration efforts.

Agrilus planipennis, the emerald ash borer (EAB), is a destructive invasive forest pest decimating North American ash trees. Population-wide management of EAB focuses on biological control, with the introduction of four parasitic wasps; one egg parasitoid, Oobius agrili and three larval parasitoids- Spathius galinae, Spathius agrili and Tetrastichus planipennisi. This thesis examines some of the factors influencing the establishment of these larval biocontrol agents. Chapter 1 examines the relationship between woodpeckers and the parasitoids S. agrili and T. planipennisi. Both woodpeckers and these parasitoids attack the larval stage of EAB, which means their impacts overlap and potentially interact. To examine this relationship, I established parasitized larvae on ash trees and then used screening to exclude woodpeckers from some sections of the tree. Results show that while there is no evidence of discriminatory feeding for or against parasitized larvae, the presence of parasitized larvae changes woodpecker feeding behavior at a stand-level. I hypothesize that this change is due to these larval parasitoids being a low-food reward and that parasitism contributes to a change and decrease in patch quality, causing woodpeckers to quit foraging sooner than usual. My second chapter focuses on Spathius galinae, which was recently approved for release in the north central and northeastern US in 2015, to provide additional population control. Spathius galinae’s long ovipositor (4-5.3mm) is theoretically expected to help target EAB in ash with larger diameters and bark thicknesses. Using experimentally infested logs of varying thicknesses in the laboratory I tested the limits and preferences for oviposition of S. galinae, to understand its potential impact on EAB. My results demonstrated that although parasitism by S. galinae drops significantly when bark thickness reaches 8 mm, this prevents S. galinae only from reaching EAB larvae in my largest ash trees (S. galinae will play a vital role in providing additional control and in supporting ash regeneration in aftermath areas of EAB invasions.

Orientador: Carmen Regina Marcati / Resumo: A casca é um sistema biológico complexo que desempenha diversas funções na planta, incluindo condução de fotoassimilados, suporte mecânico, armazenamento de substâncias e proteção contra herbívoros, patógenos e intempéries como o fogo. A casca é composta, principalmente, pelo floema secundário e pela periderme, e reveste tanto caules quanto raízes. O caule está exposto à atmosfera e tem funções de elevação e suporte da planta, enquanto a raiz está exposta ao solo e tem funções de fixar a planta ao solo, armazenar substâncias e absorver e conduzir água e nutrientes. Contudo, pouco se sabe se as diferentes funções de caules e raízes indicam diferentes funções na casca de cada órgão. Neste trabalho, comparamos a casca de caules e raízes de 15 espécies representativas do cerrado paulista e testamos se a casca do caule apresentaria funções de suporte e proteção, enquanto a casca da raiz apresentaria função de armazenamento de substâncias. Também testamos se encontraríamos maior eficiência na condução de fotoassimilados na casca da raiz. Para tanto, selecionamos 15 espécies de árvores e arbustos do cerrado sensu stricto e amostramos a casca do caule e da raiz. Analisamos a estrutura (espessura e anatomia), a densidade e a química (água, açúcares solúveis, amido, nitrogênio, fósforo e carbono) e relacionamos com as funções da casca em cada órgão. Na casca do caule, encontramos maior espessura da periderme, devido ao felema mais largo com células maiores e mais espessas, e menor dens... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Bark is a complex biological system that performs multiple functions in plant, including photoassimilates conduction, mechanical support, storage and protection against herbivores, pathogens and fire. Bark comprises mainly the secondary phloem and the periderm, and covers both trunks and roots. The trunk is exposed to the atmosphere and has the main functions of plant elevation and plant support, whereas the root is exposed to the ground and has the main functions of fix the plant to the ground, store substances, provide water and nutrients to the plant. However, remain unclear whether the different functions of trunk s and roots indicate different functions in the bark of each organ. In this work, we compared the bark of trunk and roots of species in the cerrado of São Paulo, tested whether the trunk bark presents both support and protection functions, whereas the root bark presents storage function. We also tested whether we would find higher efficiency of photoassimilates conduction in the root bark. For this purpose, we selected 15 representative species of trees and shrubs in the cerrado sensu stricto and sample both trunk and root barks. We analyzed the structure (thickness and anatomy), density and chemistry (water, soluble sugars, starch, nitrogen, phosphorus and carbon) and associated to the bark functions in each organ. In the trunk bark, we found thicker periderm, due to thicker phellem with larger cell and thicker wall cells, and lower periderm density, suggesting... (Complete abstract click electronic access below) / Doutor

The results of bark thickness analysis of pine and spruce trees at the thinning age are presented in the work. The main goal of the work was to investigate regularities of bark thickness variance of pine and spruce logs produced out of trees felled during the thinning cuttings. The main tasks of the work were to find out regularities of bark thickness variance depending on age of the stands, tree species and top diameter of the log, to evaluate adequateness modeled regularities to existing Swedish normatives. The empirical material. 200 pine and 200 spruce felled trees at the Kazlu Ruda state forest enterprise were used for the measurements. The trees were selected at the 4 cutting areas of Nb, Lb, Lc, site types. Diameter and bark thickness of imaginative crosscut at height of 0, 1, 1.3, 3 m and following each second meter were measured for each stem. Methods. The multiple linear and nonlinear regression were used to process empirical data. Calculations were made using software STATISTICA v6.0 and EXCEL. The main results. The differences of bark thickness variation regularities were found while comparing gotten results to Existing Lithuanian and Swedish legalized normatives.

Darbe pateikti beržų, drebulių, juodalksnių žievės storio tyrimai. Tyrimo tikslas: Išanalizuoti beržų, drebulių, juodalksnių stiebų žievės storio kintamumo dėsningumus ir jų pagrindu sudaryti stiebų žievės matematinį modelį. Tyrimo uždaviniai: Nustatyti beržo, drebulės, juodalksnio žievės storio koreliacinius ryšius su stiebų taksacinėmis charakteristikomis. Nustatyti beržų, drebulių, juodalksnių žievės storio kitimo dėsningumus išilgai stiebo ir išreikšti juos regresinėmis lygtimis. Išreikštus beržų, drebulių, juodalksnio žievės storio kitimo dėsningumus palyginti su galiojančiais normatyvais, kitų tyrėjų rezultatais. Tyrimo objektas: Tyrimo bareliuose paimti beržų, drebulių, juodalksnių medžių stiebai iš vidurio Lietuvos ir Žemaitijos regionų. Iš viso tyrimui buvo išmatuota 175 beržo, 136drebulių, 152 juodalksnio stiebų duomenys. Tyrimo metodai: žievės storio priklausomybė nuo jį sąlygojančių veiksnių buvo analizuojama daugianarės tiesinės ir kreivinės regresinės analizės metodais panaudojant EXCEL ir statistika V.6.0 programas. Tyrimo rezultatai: Išanalizuoti beržų, drebulių, juodalksnių kintamumai. Gauti empiriniai duomenys palyginti su kitų autorių matavimo rezultatais, atliekant žievės storio priklausomybės nuo stiebo skersmens 1.3 m aukštyje lyginamąją analizę. Gauti beržų, drebulių juodalksnių žievės storio kintamumo modeliai. / The results of bark thickness analyses of birch, aspen, black alder tree species are presented in the work. The main goal of the work was to investigate regularities of bark thickness variance of birch, aspen, black alder logs felled during all cutting and to make mathematical model of bark of stems. The main tasks of the work were to find out regularities of bark thickness of asp, birch, black – alder and bark thickness dependence on parameters of stems, to make regression analysis of regularities of bark thickness variance along stem and to compare results of work with other similar investigations. The empirical material of asp, birch and black -alder stems were selected from the middle and lowland regions of Lithuania. Overall 465 records of stem were collected, of which 175 records were of aspen, 136 – of birch, 152 – of black-alder. Methods The multiple linear and nonlinear regressions were used to process empirical data. Calculations were made using software STATISTICA v6.0 and MS EXCEL packages. The main results Changes of bark thickness of birch, aspen and black alder were investigated. The acquired empirical data were compared with the data of other authors carrying out comparative analyses of bark thickness dependence on steam diameter at 1.3 m height. Models of bark thickness variance of birch, aspen, black alder were prepared.