Combining tradition and innovation, timber plays essential roles in building structures for architecture and engineering. Tree branching geometries and timber in its natural state often serve as sources of inspiration. However, the mechanical properties of naturally grown timber, inherently inconsistent and geometrically varied, remain insufficiently studied, particularly for construction and simulations. This knowledge gap perpetuates the prevalent use of straight, uniformly harvested timber while neglecting curved and bifurcated elements with smaller cross-sections.

This research investigates the potential of naturally grown timber in structural design, emphasizing the importance of understanding the natural characteristics and growth patterns of trees to optimize timber use. The developed methodology leverages noninvasive technologies, such as computerized tomography (CT), to precisely capture the geometrical and material properties of wood. These data sources are then integrated to visualize cross-sectional geometries and material properties, forming the basis for our analytical approach. Utilizing generalized scaled boundary isogeometric analysis, the methodology enhances the accuracy and efficiency of simulations, aligning structural design with natural growth principles. This approach not only fosters sustainable resource practices by promoting the use of major tree parts but also transforms discarded materials into valuable resources. The paper concludes with a demonstration of this methodology applied in a practical construction scenario.

To estimate the potential growth and distribution of itchgrass (Rottboellia exaltata L. f.) in the United States, we grew the plant in 36 combinations of day and night temperatures in controlled-environment greenhouses. Day temperatures ranged from 17 to 32 C and night temperatures from 11 to 26 C. Total dry weights, leaf areas, heights, and numbers of tillers were determined at 3, 31, and 58 days after emergence. Mathematical growth analysis techniques were used to calculate net assimilation rates (NAR) and leaf area durations (LAD). Maximum dry matter production (the product of NAR and LAD) and maximum leaf area production occurred at 32/26 C. Dry matter production and leaf area production were greatly reduced by day temperatures below 29 C and night temperatures below 23 C. The retardation of dry matter production by low night temperature was due mainly to reductions in LAD rather than to reductions in NAR. Low day temperatures reduced dry matter production through combined effects on LAD and NAR. At the warmer day temperatures, tiller production increased with decreasing night temperature. Flowering occurred at all day temperatures and at all night temperatures of 14 C or greater. Based on its growth responses to temperature, itchgrass would reach 75 to 100% of its maximum potential growth in the Gulf Coast states, the lower Midwest, the South Atlantic states, and the Southwest. Therefore, it represents a serious potential weed problem in these regions.

Cotton was grown alone (one plant/pot), in intraspecific competition (two plants/pot), and in interspecific competition with spurred anoda and velvetleaf in controlled-environment chambers, subjected to water stress by withholding water, and allowed to recover before the final harvest. Minimum leaf water potential reached during the drought period ranged from −1.87 MPa in cotton grown alone to −2.63 MPa in velvetleaf grown in intraspecific competition. Water stress reduced plant height, total dry weight, and leaf area in all species, compared to well-watered controls. Reductions in cotton growth due to intra- or interspecific competition were evident by 11 days following the onset of competition. The competitive impact of both weeds tended to increase with time. Growth reductions in cotton due to competition were associated primarily with reductions in leaf area duration; during drought the net assimilation rate also was reduced. Relative yields of cotton confirmed that interspecific competition from the weeds was more severe than intraspecific competition. Imposed drought did not affect the relative competitive abilities of the three species or the impact of the weeds on cotton.

Vegetative growth response of round-leaved mallow to various day/night temperature regimes was studied under controlled-environment conditions to predict its potential geographic distribution and to develop an effective control program. Round-leaved mallow dry matter production was greatest with day temperatures of 18 to 26 C. Dry matter accumulation was reduced by a night temperature of 6 C but was minimally affected by night temperatures ranging from 12 to 24 C. Regression analysis predicted minimal vegetative growth at mean daily temperatures below 8 C and above 30 C, with optimum growth at 20 C. Partitioning of round-leaved mallow biomass in leaves, stems, and roots was affected by temperature. Maximum leaf weight ratio occurred at low temperatures, 10 C day and 6 C night. Stem weight ratio was greatest at a day temperature of 26 C, with night temperature having little effect. Maximum root biomass occurred with a day temperature of 18 C. Results are discussed in terms of environmental conditions that allow round-leaved mallow to be an effective competitor with crops and potential approaches for its control.

Velvetleaf (Abutilon theophrasti Medic. ♯3 ABUTH) grown under monoculture consistently exceeded velvetleaf intercropped with soybeans [Glycine max (L.) Merr. var. ‘Amsoy 71′] in leaf area, nodes with fully developed leaves, canopy width, branches, and number of capsules as early as 3, 3, 4, 5, and 8 weeks, respectively, after simultaneous emergence. Velvetleaf plants without soybean competition eventually developed over nine times the dry matter of velvetleaf intercropped with soybean. The only components of velvetleaf plants sampled which sometimes increased significantly when soybean was defoliated in a manner simulating damage caused by the green cloverworm (GCW) (Plathypena scabra F.) were leaf area, number of leaves, and number of main-stem nodes. Soybeans in Iowa are attacked by the GCW late enough in the growing season that velvetleaf surviving previous weed management efforts benefited only slightly.

Growth characteristics and competitive relationships of cotton and three perennial weeds (johnsongrass, purple nutsedge, and yellow nutsedge) were investigated at the USDA Cotton Research Station in Shafter, CA. In growth analysis experiments, yellow nutsedge and johnsongrass had highest values for height, biomass, leaf area production, growth rate, and photosynthetic efficiency. The weeds exhibited greater overall resource use and production efficiency than cotton, while cotton attained greater leafiness and canopy closure than weeds over the 10-wk experiment. Linear correlation indicated that most growth variables were significantly correlated with aggressivity (competitiveness); however, all correlation coefficients were less than 0.80. Stepwise multiple regression, using aggressivity as the dependent variable, defined 4 growth variables out of 12 that best described competitiveness. These were unit leaf rate (ULR), height, relative growth rate (RGR), and initial propagule weight (PWT). Thus, parameters of light utilization (ULR, height) and early establishment (RGR, PWT) were best predictors of competitive success in this system.

Velvetleaf from Mississippi and Wisconsin and soybean (var. Williams) were grown in five temperature regimes (12/4, 19/11, 26/18, 33/25, and 40/32 C day/night) in controlled-environment chambers. Leaf appearance rates increased with temperature in both species, ranging from 0.06 to 0.69 leaves per day in velvetleaf and 0.07 to 0.38 leaves per day in soybean. The threshold temperature for leaf appearance in both species was 5 to 6 C. The largest leaves of both species were produced at 26/18 C. By 55 d after emergence, the greatest total leaf area per plant occurred at 26/18 C or above in both species. Reproductive development occurred earliest at 33/25 C in velvetleaf and at 26/18 C in soybean. This limited vegetative growth in velvetleaf more than in soybean. The weed/crop ratio for total leaf area increased with increasing temperature, indicating that velvetleaf probably would be more competitive with soybean under higher temperatures. The two populations of velvetleaf generally responded similarly to temperatures.

Effects of temperature and interference were examined in a replacement series experiment with cotton (Gossypium hirsutum L. 'Stoneville 213′), spurred anoda Anoda cristata (L.) Schlecht. # ANVCR), and velvetleaf (Abutilon theophrasti Medic. # ABUTH). Plants were grown in controlled-environment greenhouses at day/night temperatures of 32/23 or 26/17 C, and harvested 14 or 39 days after planting. Height, dry weight, and leaf area at both harvests, and dry matter production and leaf area duration for the harvest interval were significantly greater in all species at 32/23 C than at 26/17 C. Interference reduced the dry weight per plant and leaf area at day 39, and dry matter production for the harvest interval. Cotton was somewhat superior to both weeds as a competitor at 32/23 C, while spurred anoda was somewhat superior to cotton and velvetleaf at 26/17 C.

Field experiments were established in 1989 and 1990 at the Southern Piedmont Conservation Research Center near Watkinsville, GA, to determine effects of coastal bermudagrass density on cotton in a conservation tillage system. Cotton height, canopy width, leaf area indices, and seed cotton yields were determined at coastal bermudagrass densities of 0 to 3600 kg ha−1 as achieved by herbicide inputs. Soil water measurements were recorded in cotton plots with a range of coastal bermudagrass densities using time domain reflectometry. Cotton growth and yields were reduced by coastal bermudagrass competition both years of the study. At the highest coastal bermudagrass density of 3600 kg ha−1, cotton height was reduced compared to cotton alone as early as 5 wk after planting. Seed cotton yields were reduced 25% at the highest coastal bermudagrass densities both years of the study. At the 15-cm soil depth, coastal bermudagrass significantly reduced soil water in cotton. Soil water in cotton at 30, 45, and 60 cm was not affected by coastal bermudagrass.

Mathematical growth analysis techniques were used to evaluate the effects of CO2 concentrations of 350, 600, and 1000 ppm (v/v) on growth and biomass partitioning in corn (Zea mays L. ‘Dekalb XL 395’), itchgrass (Rottboellia exaltata L. f.), soybean [Glycine max (L.) Merr. ‘Tracy’], and velvetleaf (Abutilon theophrasti Medic). Controlled environment chambers with day/night temperatures of 28/22 C and photosynthetic photon flux densities (PPFD) of 650 μE (microeinsteins) m-2 s-1 were used. Dry matter production in the two C3 species (soybean and velvetleaf) was increased significantly by raising the CO2 concentration above 350 ppm. In corn (a C4 species), dry matter production was least at 1000 ppm CO2 and did not differ between the 350 and 600 ppm treatments. In itchgrass (also C4), dry matter production was greatest at 600 ppm CO2 and did not differ between the 350 and 1000 ppm treatments. Increasing the CO2 concentration increased the rate of dry matter production per unit leaf area (net assimilation rate or NAR) in soybean and velvetleaf but either decreased or did not alter NAR in corn and itchgrass. At 45 days after planting, the weed/crop ratios for total dry matter production for velvetleaf/corn and itchgrass/corn were significantly greater at both 600 and 1000 ppm than at 350 ppm CO2. The weed/crop ratio for itchgrass/soybean was less at 1000 ppm than at 350 or 600 ppm CO2. Compared to the value at 350 ppm, the weed/crop ratio for velvetleaf/soybean was greater at 600 ppm and less at 1000 ppm CO2. We conclude that atmospheric CO2 enrichment probably will make weeds with the C3 photosynthetic pathway more competitive with crops having the C4 pathway. Weeds with the C4 pathway may become less competitive with crops having the C3 pathway.

The effects of shade on the growth and photosynthetic capacity of the exotic noxious weed itchgrass (Rottboellia exaltata L. f.) were determined under controlled environment conditions. The plants were grown at day/night temperatures of 29/23 C under 100, 60, 25, and 2% sunlight in a climate-controlled greenhouse. Mathematical growth analysis techniques were used to evaluate the effects of shading on dry matter production and leaf area production. Infrared gas analysis and diffusion porometry techniques were used to evaluate the effects of shading on photosynthesis and stomatal resistance. Shading markedly reduced dry matter production. At 40 days after planting, plants grown in 2, 25, and 60% sunlight had 0.3, 16, and 55%, respectively, of the dry weight of the plants grown at 100% sunlight. Leaf area production was less severely retarded by shading; the plants grown at 2, 25, and 60% sunlight had, respectively, 1.7, 42, and 99% of the leaf area of the plants grown at 100% sunlight. Ambient photosynthetic rates of recently expanded, single, fully exposed leaves were 22.5, 51.6, and 65.5 mg CO2 dm-2h-1 in the 25, 60, and 100% sunlight treatments, respectively. Photosynthetic rates at saturating irradiance did not differ significantly in plants grown at 25, 60, or 100% sunlight and ranged from 76.4 to 78.0 mg CO2 dm-2h-1. Stomatal resistances, ranging from 6.0 to 7.5 s cm-1, also did not differ significantly among these plants. In terms of dry matter production, itchgrass is a shade-intolerant plant. However, even when grown in shade, itchgrass maintains the capacity for high photosynthetic rates and high growth rates when subsequently exposed to high irradiance. These characteristics help explain its competitiveness with crop species.

Showy crotalaria (Crotalaria spectabilis Roth) was grown in a controlled-environment greenhouse with a day/night temperature of 32/26C at full sunlight and under 40, 60, or 90% shade. Shading significantly reduced height, dry-matter accumulation, leaf production, leaf-area expansion, axillary-branch development, reproductive development, and the partitioning of plant biomass into stems. Shading increased the partitioning of plant biomass into leaves and the leaf area ratio. Constant shading or shading from 0 through 25 days after planting reduced the leaf area duration (LAD) proportionally more than the net assimilation rate (NAR). Shading from 25 to 67 days after planting reduced NAR and LAD equally. In other experiments reducing the day/night temperature below 32/26C significantly reduced plant height, leaf area, and the rate of leaf production. Dry-matter production decreased significantly at temperatures below 29/23C, because of substantial reduction in LAD. Showy crotalaria flowered and produced seed at temperatures ranging from 23/17C to 32/26C. The results indicate that the geographical distribution of showy crotalaria in the United States probably will continue to increase.

Dose-response studies estimating GR40 values indicated different levels of propanil resistance in junglerice populations from fields previously treated with propanil, compared to a check population collected where this herbicide had never been used. The GR40 for susceptible populations ranged from 0.36 to 0.50 kg ai ha−1 and for resistant populations ranged from 1.10 to 3.10 kg ai ha−1. Considerable variability in growth and morphology existed among populations. Variability in cumulative leaf area, aboveground biomass, mean relative growth rate, mean net assimilation rate, and mean leaf area ratio could not be related to propanil resistance. Competitiveness was not related to propanil resistance either. of several vegetative and reproductive parameters measured at maturity, only grain weight per plant and number of grains per plant were correlated with GR40 (r = −0.73, P = 0.06). This trend towards lower reproductive fitness in propanil-resistant junglerice plants may reduce its ecological success when growing with propanil-susceptible plants in the absence of this herbicide.

Achene germination of common crupina (Crupina vulgaris Cass. ♯ CJNVU) was 86% or greater at day/night temperatures ranging from 15/4 to 29/25 C. Germination was greatly reduced at a day temperature of 36 C, regardless of the night temperature. The time required for maximum germination (9 to 19 days) increased with decreasing night temperature. Maximum leaf area, rosette diameter, and dry-matter accumulation during vegetative growth occurred at 22/18 to 29/25 C, 22/18 C, and 22/18 C, respectively. The plants attained 50% or more of maximum dry-matter accumulation at day/night temperatures ranging from as low as 22/4 and 15/11 C to as high as 36/25 C. Net assimilation rate was relatively insensitive to growth temperature. Rosettes of common crupina grown at 22/11 or 29/18 C exhibited almost complete photosynthetic and respiratory temperature acclimation. Increasing the photoperiod from 10 to 12, 14, or 16 h accelerated flowering. Maximum achene production occurred in the 16-h photoperiod, but viable achenes were produced in all photoperiods. Temperature during vegetative growth influenced subsequent responses to photoperiod. Plants grown for 83 days in a 14-h photoperiod at 15/4 or 22/11 C and transferred to 26/20 C flowered and produced seed in photoperiods of 8 or 16 h. Plants grown at 29/18 or 36/25 C subsequently flowered only in the 16-h photoperiod at 26/20 C. Common crupina has a wide tolerance of variations in temperature and photoperiod. Its range in the United States can be expected to continue to increase.

Cotton (Gossypium hirsutum L. ‘Coker 315’), spurred anoda [Anoda cristata (L.) Schlecht. # ANVCR], and velvetleaf (Abutilon theophrasti Medik. # ABUTH) were grown in controlled-environment chambers at 29/23 C day/night temperature and 1000 μE·m–2·s–1 photosynthetic photon flux density (PPFD). Groups of plants were subjected to water stress by withholding water for 8 days, beginning at 27 days after planting. Cotton reached a lower leaf water potential than spurred anoda and velvetleaf following 8 days of withholding water. Following the drought, plants were rewatered for a 6-day recovery period. Water stress reduced plant height, leaf number, leaf area, total dry weight, stomatal conductance, transpiration, net assimilation rate, and leaf area duration in all species, in comparison with well-watered controls. Water stress decreased partitioning of plant biomass into leaves and increased partitioning into roots. Following rewatering, stomatal conductance and transpiration rates of previously stressed plants recovered to control levels within 28 h. Net assimilation rates of previously stressed spurred anoda also recovered to control levels. After 6 days of recovery, total dry weights and leaf areas of previously stressed plants of all three species remained below those of control plants. The overall effect of the drought and water stress was to delay the time at which spurred anoda and velvetleaf equaled or surpassed cotton in dry weight and leaf area, suggesting that drought early in the growing season under field conditions might increase the competitiveness of cotton relative to the two weeds.

Field horsetail was grown from rhizome segments for 28 and 52 d under 35, 60, 120, 170, and 320 μmol m–2 s–1 photosynthetic photon flux (PPF) and four continuous nitrogen (N) supply rates corresponding to a total of 1 to 6 kg N ha–1 28 d after planting (DAP) and 6 to 41 kg N ha–1 52 DAP. There was no response to the supply of N in the first growth period, probably due to the mobilization of nitrogen available in the planted rhizomes, and only dry weight (DW) of new belowground production, mostly roots, responded to increased light. Rhizomes were produced during the latter part of the 52-d period. Requirements for light and N during the 52-d period were low, because total new tissue production was only reduced at the lowest levels of light (35 μmol m–2 s–1 PPF) and the two lowest N supply rates (6 and 18 kg N ha–1). The ratio of shoot DW to belowground organ DW increased only as the N supply increased. Shoot height response to an increased N supply was also small. Field horsetail can therefore be considered tolerant of low levels of N but will be overtopped by fast-growing species when competing for increased supplies of N. Both an increase in N supply and a reduction in light increased the reduction of DW of the planted rhizomes, whereas tuber production was favored by low N supply and high light intensities. Field horsetail can tolerate low levels of N but is not likely to be competitive in a dense crop stand.

Texas panicum was grown in controlled-environment chambers in 16 day/night temperature regimes ranging from 19/11 to 34/26 C. After 33 days, maximum plant height, leaf area, and dry weight occurred at 34/26 C. The greatest number of tillers and leaves occurred at 34/16 C. Partitioning of plant biomass into stems increased with increasing night temperature, while partitioning into leaves tended to decrease. Partitioning of biomass into roots decreased with increasing night temperature at day temperatures of 19 or 24 C but not at 34 C. Plant dry matter production (DMP) was highly correlated with both leaf area duration (LAD) and net assimilation rate (NAR) during the first 2 weeks of growth. During the subsequent 3 weeks, DMP was highly correlated with LAD but not with NAR. The low-temperature threshold for growth of Texas panicum was approximately 11 C. Texas panicum attained 25% of its maximum growth at an average daily temperature of 21 C, 50% at 24 C, and 75% at 26 C. Texas panicum is unlikely to become a highly competitive weed outside the southern and southwestern United States.

Goatsrue, a perennial legume, is an exotic noxious weed currently found in the United States only in Cache County, Utah. It infests irrigated pastures, alfalfa fields, and noncropland areas. In order to compare their responses to temperature, goatsrue and alfalfa were grown in artificially illuminated controlled-environment chambers in 16 day/night temperature regimes ranging from 15/4 to 36/25 C. Growth analysis was used to evaluate effects of temperature on dry matter accumulation, leaf area production, and biomass allocation. Both species grew best at day/night temperatures of 22/25, 29/ 18, and 29/25 C. Leaf appearance rates were linearly related to mean daily temperature. Goatsrue produced fewer but larger leaves and a greater total leaf area than alfalfa. Biomass partitioning to leaves was greater in goatsrue, whereas partitioning to stems was greater in alfalfa. Response of vegetative dry matter production to temperature closely paralleled response of leaf area duration in both species. Alfalfa generally had a higher net assimilation rate, but the greater leaf area duration of goatsrue resulted in greater dry matter accumulation in this species after 50 d of growth. Overall responses to temperature were similar in the two species. Thus it seems likely that goatsrue could become a much more widely distributed weed in alfalfa.

Sicklepod (Cassia obtusifolia L. ♯6 CASOB), hemp sesbania [Sesbania exaltata (Raf.) Cory ♯ SEBEX], and showy crotalaria (Crotalaria spectabilis Roth. ♯ CVTSP) were grown in controlled-environment greenhouses with day/night temperatures of 23/17, 26/20, 29/23, and 32/26 C. Plant height, leaf area, and total dry weight at 53 days after planting increased significantly with temperatures between 23/17 and 29/23 C in sicklepod and showy crotalaria, and between 23/17 and 32/26 C in hemp sesbania. In all species, leaves were produced more rapidly as temperature increased. Axillary branch leaf production was greatest at 29/23 C in sicklepod, and at 29/23 and 26/20 C in showy crotalaria; hemp sesbania showed little axillary branch development. Total dry-matter production in all species was closely correlated with leaf area duration, but not with net assimilation rate. Differences in total main stem leaf area in all species were primarily due to differences in leaf number rather than to differences in leaf size at maturity.

Comparative growth, development, and resource allocation of triazine - susceptible and triazine - resistant biotypes of common groundsel (Senecio vulgaris L.), grown under two light regimes, were studied over a 7 - week period. Dry-matter production, height, number of leaves, and leaf area of the susceptible biotype were greater than those of the resistant biotype at all harvests under both light regimes. Root/shoot ratios were lower in the resistant than in the susceptible biotype under high light. Lower values for these parameters in resistant plants are due to lowered photosynthetic capacity, which limits growth and lowers relative root production. Net assimilation rate (NAR) was lower in resistant than susceptible plants when grown under high light, but mean leaf area ratio over a harvest interval (L) of resistant plants was higher than that of susceptible plants under high light. Relative growth rate (RGR) was higher for susceptible plants before day 42 and higher for resistant plants after day 42 under high light. A lower plastochron index (PI) of resistant plants up to 5 weeks old, relative to susceptible plants of the same age, suggests that, when grown under high light, resistant plants are developmentally at least 2 days behind susceptible plants. Shading lowered dry-weight production, height, number of leaves, leaf area, NAR, RGR, PI and root/shoot ratios of both biotypes. Values for these growth parameters for susceptible plants were similar to or larger than for resistant plants when grown under low light. In both biotypes, resource allocation patterns and L shifted towards increased shoot and leaf production in response to shading.