Comparing the financial performance of traditionally managed beech and oak stands with roomy established and pruned stands

Beech and oak stands are normally established with high numbers of plants. On one hand, this costs a lot, but on the other hand, knot-free timber may be expected only in this way. This study analyses whether roomy establishment and, as a result, lower timber quality lead to financial advantages over the normal treatment. In addition to this, it is tested if pruning of roomy established beech and oak stands is financially advantageous. For this valuation, conventionally managed stands were simulated with the forest growth simulator Silva and for the roomy established stands, data from trial plots were completed with Silva. The development of the pruned oak stands followed the yield table of Jobling and Pearce (Free growth of oak, Forest record number 113, Forestry Commission HMSO, London, 1977), while for beech the development of the diameters orientated to an investigation of Hasenauer et al. (Österr Forstztg 105:28–29, 1994). Based on the assortments contained in the stands, a valuation of the different treatments was done with annuities within a Monte Carlo simulation, thereby including the volatility of timber prices and the risk of natural hazards. Additionally, the imputed costs per cubic meter of produced timber and the minimum share of high-value assortments on the pruned trunks were calculated for the required rates of return of 1, 2 and 3%. The conventionally managed beech and oak stands were found to be inferior from the financial point of view. Even the non-pruned stands with roomy establishment were superior despite the lower timber quality. The minimum share of high-value assortments on the pruned trunks were between 6 and 410%. Particularly in the case of high values of the land, the maximum volume of high-value assortments was not sufficient to achieve certain rates of return. Nevertheless, the stands with pruning and low-density management were more profitable. In addition to this, it was ascertained that pruning of beech and oak is possible and does not hinder the production of high-value assortments.     

Parenchyma cell growth in potato tubers I. Different tuber regions

Enlargement rates of starch-storage parenchyma cells during growth of Kennebec and Russet Burbank potato cultivars were determined for cortical, perimedullary, and pith tissuues of bud ends, midsections, and stem ends of tubers. Average volumetric size of parenchyma cells increased 7 to 18x during growth of Russet Burbank tubers, with the greatest increases occurring in cortical and perimedullary cells of bud ends and midsections, and the least in stem ends and pith tissues. In Kennebec tubers parenchyma cells in both stem end and midsection increased only 5 to 8 x, whereas increases in bud ends ranged from 8 to 20 times. Cell enlargement to tuber enlargement ratios appproached unity early in growth of Russet Burbank tubers. As tubers increased beyond the 45 g size, cell enlargement and tuber enlargement rates were essentially equal. Calculations of cells per unit tissue volume agreed with ratio determinations. The timing of such unity appeared to be delayed in Kennebec tubers, and was not quite as pronounced as in Russet Burbank tubers. This may have been due to differences in growth rates of individual tubers in response to cultural conditions. In general, cells of harvestmature Kennebec tubers were about 60% as large as similar cells of Russet Burbank tubers.     

Hydraulic traits and tree-ring width in <Emphasis Type="Italic">Larix sibirica</Emphasis> Ledeb. as affected by summer drought and forest fragmentation in the Mongolian forest steppe

Key message

Wood-anatomical traits determining the hydraulic architecture of Larix sibirica in the drought-limited Mongolian forest steppe at the southern fringe of the boreal forest respond to summer drought, but only weakly to variations in microclimate that depend on forest stand size.

Context

Siberian larch (L. sibirica Ledeb.) is limited by summer drought and shows increasing mortality rates in the Mongolian forest steppe. The climate sensitivity of stemwood formation increases with decreasing forest stand size. The trees’ hydraulic architecture is crucial for drought resistance and thus the capability to deal with climate warming.

Aims

We studied whether hydraulic traits were influenced by temporal or forest size-dependent variations in water availability and were related to tree-ring width.

Methods

Hydraulic traits (tracheid diameter, tracheid density, potential sapwood area-specific hydraulic conductivity) of earlywood were studied in stemwood series of 30 years (1985–2014) and were related to climate data. Tree-ring width was measured for the same period. Trees were selected in stands of four different size classes with increasing drought exposure with decreasing stand size.

Results

Tracheid diameters and hydraulic conductivity decreased with decreasing late summer precipitation of the previous year and were positively correlated with tree-ring width. Forest stand size had only weak effects on hydraulic traits, despite known effects on stemwood increment.

Conclusion

Decreasing tracheid diameters and thus hydraulic conductivity are a drought acclimation of L. sibirica in the Mongolian forest steppe. These acclimations occur as a response to drought periods but are little site-dependent with respect to stand size.

     

Effects of zilpaterol hydrochloride and days on the finishing diet on feedlot performance, carcass characteristics, and tenderness in beef heifers

British × Continental heifers (n = 3,382; initial BW = 307 kg) were serially slaughtered to determine if increasing days on the finishing diet (DOF) mitigates negative consequences of zilpaterol HCl (ZH) on quality grade and tenderness of beef. A 2 × 3 factorial arrangement of treatments in a completely randomized block design (36 pens; 6 pens/treatment) was used. Zilpaterol HCl (8.33 mg/kg DM) was fed 0 and 20 to 22 d before slaughter plus a 3 to 5 d withdrawal to heifers spending 127, 148, and 167 DOF. Feedlot and carcass performance data were analyzed with pen as the experimental unit. Three hundred sixty carcasses (60 carcasses/treatment) were randomly subsampled, and strip loin steaks were aged for 7, 14, and 21 d for assessment of Warner-Bratzler shear force (WBSF) and slice shear force (SSF) with carcass serving as the experimental unit for analysis. No relevant ZH × DOF interactions were detected (P > 0.05). Feeding ZH during the treatment period increased ADG by 9.5%, G:F by 12.5%, carcass ADG by 33.6%, carcass G:F by 35.9%, carcass ADG:live ADG by 15.6%, HCW by 3.2% (345 vs. 356 kg), dressing percent by 1.5%, and LM area by 6.5% and decreased 12th-rib fat by 5.2% and yield grade (YG) by 0.27 units (P < 0.01). Feeding ZH tended to decrease marbling score (437 vs. 442 units; P = 0.10) and increased WBSF at 7 (4.25 vs. 3.47 kg; P < 0.01), 14 (3.57 vs. 3.05 kg; P < 0.01), and 21 d (3.50 vs. 3.03 kg; P < 0.01). Feeding ZH decreased empty body fat percentage (EBF; 29.7% vs. 30.3%; P < 0.01) and increased 28% EBF adjusted final BW (473.4 vs. 449.8 kg; P < 0.01). Analysis of interactive means indicated that the ZH × 148 DOF group had a similar percentage of USDA Prime, Premium Choice, Low Choice, and YG 1, 2, 3, 4, and 5 carcasses (P > 0.10) and decreased percentage of Select (30.4 vs. 36.6%; P = 0.03) and Standard (0.2 vs. 0.9%; P = 0.05) carcasses compared with the control × 127 DOF group. As a result of ZH shifting body composition, extending the DOF of beef heifers is an effective feeding strategy to equalize carcass grade distributions. This can be accomplished along with sustaining the ZH mediated advantages in feedlot and carcass weight gain.