Forest Carbon Storage in the Northeastern United States: Effects of Harvesting Frequency and Intensity Including Wood Products

Temperate forests are an important carbon sink, yet there is debate regarding the net effect of forest management practices on carbon storage. Few studies have investigated the effects of different silvicultural systems, and the relative strength of in-situ forest carbon versus wood products pools remains in question. Our research (1) describes the impact of harvesting frequency and degree of post- harvest structural retention on carbon storage in northern hardwood-conifer forests, and (2) tests the significance of including harvested wood products in carbon accounting at the stand scale. We stratified Forest Inventory and Analysis (FIA) plots to control for environmental, forest structural and compositional variables, resulting in 32 FIA plots distributed throughout the northeastern U.S. We used the USDA Forest Vegetation Simulator to project stand development over a 160 year period under nine different forest management scenarios. Simulated treatments represented a gradient of increasing structural retention and decreasing harvesting frequencies and included a “no harvest” scenario. The simulations incorporated carbon flux between aboveground forest biomass (dead and live pools) and harvested wood products (including carbon storage in landfills). Mean carbon storage over the simulation period, including carbon stored in harvested wood products, was calculated for each silvicultural scenario. We investigated tradeoffs among scenarios using a factorial treatment design and two-way ANOVA. The predictive strength of management scenarios relative to site-specific variables was evaluated using Classification and Regression Trees. Mean carbon sequestration was significantly (a = 0.05) greater for “no management” compared to any of the active management scenarios. Of the harvest treatments, those favoring high levels of structural retention and decreased harvesting frequency stored the greatest amounts of carbon. In order to isolate the effect of in-situ forest carbon storage and harvested wood products, we did not include the emissions benefits associated with substituting wood fiber for other construction materials or energy sources. Modeling results from this study show that harvesting frequency and structural retention significantly affect mean carbon storage. Our results illustrate the importance of both post-harvest forest structure and harvesting frequency in carbon storage, and are valuable to land owners interested in managing forests for carbon sequestration

Carbon storage, timber production, and biodiversity: Comparing ecosystem services with multi-criteria decision analysis

Increasingly, land managers seek ways to manage forests for multiple ecosystem services and functions, yet considerable challenges exist in comparing disparate services and balancing trade-offs among them. We applied multi-criteria decision analysis (MCDA) and forest simulation models to simultaneously consider three objectives: (1) storing carbon, (2) producing timber and wood products, and (3) sustaining biodiversity. We used the Forest Vegetation Simulator (FVS) applied to 42 northern hardwood sites to simulate forest development over 100 years and to estimate carbon storage and timber production. We estimated biodiversity implications with occupancy models for 51 terrestrial bird species that were linked to FVS outputs. We simulated four alternative management prescriptions that spanned a range of harvesting intensities and forest structure retention. We found that silvicultural approaches emphasizing less frequent harvesting and greater structural retention could be expected to achieve the greatest net carbon storage but also produce less timber. More intensive prescriptions would enhance biodiversity because positive responses of early successional species exceeded negative responses of late successional species within the heavily forested study area. The combinations of weights assigned to objectives had a large influence on which prescriptions were scored as optimal. Overall, we found that a diversity of silvicultural approaches is likely to be preferable to any single approach, emphasizing the need for landscape-scale management to provide a full range of ecosystem goods and services. Our analytical framework that combined MCDA with forest simulation modeling was a powerful tool in understanding trade-offs among management objectives and how they can be simultaneously accommodated. © 2012 by the Ecological Society of America

Extra-ocular movement restriction and diplopia following orbital fracture repair

Purpose To report a series of patients with extra-ocular movement restriction and diplopia after orbital fracture repair, and determine the effect of timing of repair and the type of implant used. Methods A chart review was conducted identifying all patients > 18 years of age at our institution between June 2005 and June 2008 who underwent orbital fracture repair, and presented with clinically significant diplopia and extra-ocular movement restriction persisting longer than one month after repair. Data collected included timing of repair, implant used within the orbit, and need for revision. Results Ten patients were identified with a mean time to primary orbital fracture repair at 9 days (range 1–48). Seven patients underwent revision of their orbital fracture repair with removal of the previously placed implant and replacement with non-porous 0.4 mm Supramid Foil, whereas one patient underwent lateral and inferior rectus recessions without revision of primary fracture repair. Titanium mesh was the intra-orbital implant found in all patients requiring revision of orbital fracture repair. All revisions resulted in resolution of clinically significant diplopia. Conclusions Clinically significant diplopia and extra-ocular movement restriction is not an uncommon complication after orbital fracture repair. In our series, there was a strong association between these complications and the use of porous titanium mesh implants. Revision of fractures significantly improved diplopia in all but one patient. This suggests that meticulous fracture repair and the use of non-porous implants primarily or secondarily may preclude the need for strabismus surgery after orbital trauma

Surgical approach to limiting skin contracture following protractor myectomy for essential blepharospasm

Purpose: To report our experience with protractor myectomy in patients with benign essential blepharospasm who did not respond to serial botulinum toxin injection, and to describe intra- and postoperative techniques that limited skin contracture while also providing excellent functional and cosmetic results. Methods: The medical records of patients with isolated, benign, essential blepharospasm who underwent protractor myectomy from 2005 to 2008 by a single surgeon were reviewed retrospectively. The technique entailed operating on a single eyelid during each procedure, using a complete en bloc resection of all orbicularis tissue, leaving all eyelid skin intact at the time of surgery, and placing the lid under stretch with Frost suture and applying a pressure dressing for 5-7 days. Results: Data from 28 eyelids in 7 patients were included. Average follow-up was 21.5 months (range, 4-76 months). Of the 28 eyelids, 20 (71.4%) showed postoperative resolution of spasm, with no further need for botulinum toxin injections. In the 8 eyelids requiring further injections, the average time to injection after surgery was 194 days (range, 78-323 days), and the average number of injections was 12 (range, 2-23 injections). All but one eyelid had excellent cosmetic results, without signs of contracture; one eyelid developed postoperative skin contracture following premature removal of the Frost suture and pressure dressing because of concerns over increased intraocular pressure. Conclusions: In our patient cohort, this modified technique resulted in excellent cosmetic and functional results and limited postoperative skin contracture

A hybrid technique to address exposure keratopathy secondary to facial nerve paresis: A combination of a lateral tarsorrhaphy and lateral wedge resection

Purpose To present the results of treating combined lower eyelid laxity, retraction and midface descent secondary to facial nerve weakness with a hybrid surgical procedure. Materials and methods A retrospective analysis of patients from January 2015 to January 2017 who underwent a hybrid surgical technique for the treatment of corneal exposure secondary to facial nerve paresis with a single surgeon was performed. Age, gender, and presence of exposure symptoms were recorded pre-operatively. Outcomes assessed included improvement of lower eyelid laxity and position, operative complications, and post-operative symptomatic relief. Results A total of 11 patients underwent unilateral eyelid surgery. All patients had symptomatic relief and good functional outcomes defined as improvement in eyelid laxity, lower eyelid position, and objective corneal exposure. No cases required reoperation during an average follow up of 174.5 days. Conclusions Combining portions of a tarsorrhaphy and lateral wedge resection technique is a simple and effective procedure to improve lower eyelid position and limit corneal exposure secondary to facial nerve paresis

Post-operative epiphora following the transcutaneous medial canthal incision

Purpose The safety profile of the transcutaneous medial canthal incision for access to the medial orbit is assessed with a focus on the risk of post-operative iatrogenic epiphora. Methods A retrospective chart review of patients undergoing medial orbitotomy via the transcutaneous medial canthal incision was performed. Patients with a minimum of 3 months of follow-up were included and post-operative complications were assessed and characterized. Results One-hundred-fifty patients were included in the study. A total of 4 complications were identified, including one each of the following: nasolacrimal duct obstruction, hypertrophic scar, suture granuloma and soft tissue infection. Only the nasolacrimal duct obstruction required surgical intervention. Discussion Access to the medial orbit has been achieved through a variety of approaches, each with their own benefits and risk profile. The transcaruncular approach has increased in usage as a means to avoid a visible cutaneous scar and decrease the risk of iatrogenic epiphora, however, there are specific patients who may have relative contraindications to this approach. The current study demonstrates the low risk profile of the transcutaneous medial canthal incision, specifically the minimal risk of iatrogenic damage to the nasolacrimal outflow system. This approach is another useful tool which orbit surgeons should be familiar with to offer as an option to patients requiring medial orbitotomy

Single Transconjunctival Incision and Two-point Fixation for the Treatment of Noncomminuted Zygomatic Complex Fracture

The ultimate goal in treating zygomatic complex fracture is to obtain an accurate, stable reduction while minimizing external scars and functional deformity. The present authors present our experiences with a single transconjunctival incision and two-point (inferior orbital rim and frontozygomatic suture) fixation in 53 patients with zygomatic complex fracture which were not comminuted. All patients had transconjunctival approaches with lateral canthal extensions, and six out of 53 patients also had an additional small (about less than 2 cm) gingivobuccal incision to achieve an accurate reduction. There were 3 minor complications, and the overall esthetics and functional results were satisfactory with a long term follow-up. Our method has the following advantages in the reduction of zygomatic complex fracture; It leaves only an inconspicuous lateral canthal scar. In addition, it provides excellent simultaneous visualization of the inferior orbital rim and frontozygomatic suture area. Hence, two-point fixation through a single incision can be performed with a satisfactory stability

Mineral soil carbon fluxes in forests and implications for carbon balance assessments

Forest carbon cycles play an important role in efforts to understand and mitigate climate change. Large amounts of carbon (C) are stored in deep mineral forest soils, but are often not considered in accounting for global C fluxes because mineral soil C is commonly thought to be relatively stable. We explore C fluxes associated with forest management practices by examining existing data on forest C fluxes in the northeastern US. Our findings demonstrate that mineral soil C can play an important role in C emissions, especially when considering intensive forest management practices. Such practices are known to cause a high aboveground C flux to the atmosphere, but there is evidence that they can also promote comparably high and long-term belowground C fluxes. If these additional fluxes are widespread in forests, recommendations for increased reliance on forest biomass may need to be reevaluated. Furthermore, existing protocols for the monitoring of forest C often ignore mineral soil C due to lack of data. Forest C analyses will be incomplete until this problem is resolved. © 2013 Blackwell Publishing Ltd

Intermediate-severity wind disturbance in mature temperate forests: legacy structure, carbon storage, and stand dynamics

Wind is one of the most important natural disturbances influencing forest structure, ecosystem function, and successional processes worldwide. This study quantifies the stand-scale effects of intermediate-severity windstorms (i.e., blowdowns) on (1) live and dead legacy structure, (2) aboveground carbon storage, and (3) tree regeneration and associated stand dynamics at four mature, mixed hardwood–conifer forest sites in the northeastern United States. We compare wind-affected forests to adjacent reference conditions (i.e., undisturbed portions of the same stands) 0–8 yr post-blowdown using parametric (ANOVA) and nonparametric (NMS ordination) analyses. We supplement inventory plots and downed coarse woody detritus (DCWD) transects with hemispherical photography to capture spatial variation in the light environment. Although recent blowdowns transferred a substantial proportion of live overstory trees to DCWD, residual live tree basal area was high (19–59% of reference areas). On average, the initial post-blowdown ratio of DCWD carbon to standing live tree carbon was 2.72 in blowdown stands and 0.18 in reference stands, indicating a large carbon transfer from live to dead pools. Despite these dramatic changes, structural complexity remained high in blowdown areas, as indicated by the size and species distributions of overstory trees, abundance of sound and rotten downed wood, spatial patterns of light availability, and variability of understory vegetation. Furthermore, tree species composition was similar between blowdown and reference areas at each site, with generally shade-tolerant species dominating across multiple canopy strata. Community response to intermediate-severity blowdown at these sites suggests a dynamic in which disturbance maintains late-successional species composition rather than providing a regeneration opportunity for shade-intolerant, pioneer species. Our findings suggest that intermediate-severity wind disturbances can contribute to stand-scale structural complexity as well as development toward late-successional species composition, at least when shade-tolerant regeneration is present pre-blowdown. Advance regeneration thus enhances structural and compositional resilience to this type of disturbance. This study provides a baseline for multi-cohort silvicultural systems designed to restore heterogeneity associated with natural disturbance dynamics