An evaluation of Repetitive Stress Injury (RSI) The WritePass Journal

An evaluation of Repetitive Stress Injury (RSI) Introduction An evaluation of Repetitive Stress Injury (RSI) IntroductionResearch evaluating the upper limb tension testMethodologyParticipantsProcedure  Data AnalysisRESULTSNature of the perceived sensory response and difference between the mouse and the non mouse handLocation of the perceived sensory responseDiscussion:Summary of the resultsTheoretical Implication:Clinical Implication:Strength of the studyLimitationsScope for future researchConclusionREFERENCESRelated Introduction The incidence of repetitive injury has steadily increased over the past decade and evidence indicates that this trend will continue. (Millender et al 1992, Byng et al 1997). In UK according to the NHS report, 1 in 50 workers has reported symptoms of repetitive stress injury (RSI) (Scot et al 2008). More recently there have been reports of increase in RSI among computer operators (Anderson et al 2008) reason being their repetitive jobs at faster pace. There is also research which reads that forcefulness and awkward position of upper limb have a direct effect on the development of repetitive stress injury (Greening et al 1999). Even though RSI is common, the causes of RSI are complex, diverse and incompletely understood till today. Amongst the most various hypotheses suggested over decades there is some evidence of involving the whole nociceptive system (Brain 2009). With respect to the RSI in upper limb, commonly reported symptoms by patients are cramps, par aesthesia, and hyperalgesia, with no major motor or sensory involvement (Scott et al 2008). And after reviewing these symptoms again and again the nervous system is said to be certainly involved directly or indirectly in all the patients of overuse injury of upper limb (Reisch et al 2005). It were these studies that have given birth to concept called Neurodynamic in the world of physiotherapy (Shacklock 1995) Neurodynamics has become progressively more accepted as part of the evaluation and management of the repetitive injuries (Blaster et al 1997). The ULTT was initially thought by Elvey (1979) as an objective assessment of the neural tissue of the upper quadrant in the examination of arm pain and local pain pattern of the upper quadrant. Fundamentals of neurodynamic testing are that the nervous system exists in physiological and mechanical continuity (Slater ET al1994). This means that when mechanical stresses when applied on the nerve may evoke physiological responses such as alteration in axonal transport or may be interneural blood flow. And physiological disturbances like diabetes may predispose a nerve to mechanical disturbances (Mackinnon et al1986). Physiotherapists’ incorporating tension tests as a part of assessment and treatment have documented that altered nerve extensibility and is a very common finding in RSI disorders. In   conjunction with symptomatology and subjective responses to these techniques, difference in the range of motion (ROM), difference in perceived response etc   between the affected and the non affected are often considered indicative of adverse neural tension, with implied assumption that such differences are not apparent in asymptomatic subjects (Butler 1989). Such assumption questions the evidence based practise and the validity of these tests (Sackett. et al 1996) Research evaluating the upper limb tension test Shacklock in 1995 concluded that ULTT for median nerve is a simple, effective and reliable method of examination to gain an impression of nerve mobility after performing test on cadavers. In 2005 Resich et al performed a study to measure the reliability and sensory response of median nerve biased on normal subjects. The limitation of the study was that it was done just on one side of body of normal individual. This therefore did not allow assessing if any variability or response existed in left and right side. Also the study was done on non keyboard workers thus the results cannot be generalised. Byng et al in 1997 conducted a research to compare the response of ULTT median nerve in asymptomatic, symptomatic key board workers and non keyboard workers. The results concluded that there was a variation in response to the nerve test among the three groups with keyboard workers having significant altered neural sensitivity when compared to non keyboard workers there by concluding the pain in key board workers is neural in origin. The shortcoming of this study was that there is no information regarding what was considered as a normal response at individual joint as there was only unilateral comparison.   Scott et al in 2008 performed a study to determine the false positive ULTT and slumps tests in healthy adults and reported there are false positive response in asymptomatic. But the study was just performed on dominant side of the body thus there can be no comparison and these results cannot be expected for the opposite arm. Also the mean age of participants was only 22 years thus cannot be generalized. Since the researchers knew the dominant side this may have contaminated the result. Thus ULTT is an undoubtedly simple, effective and reliable method of examination to gain an impression of nerve mobility but no trial has attempted to compare the variability of the neural tension test response bilaterally in normals. Without this bit of information the validity of the ULTT is questionable. Thus the aim of the study is to evaluate if there is any difference in mechano sensitivity and perceived response to median nerve ULTT test when compared bilaterally in non symptomatic female key board worker. Methodology Participants Inclusion criteria for the study were: asymptomatic female key board operators between the ages of 18- 60 years without any sensory problem of upper limb and/or neck within the last three months. Participants who complained of bit of neck pain on prolonged hours of sitting which did not radiate to shoulder or upper limb were included.   Subjects were excluded if they reported any contraindication and/or precaution (Butler, 1991) like   peripheral or central nervous system disease or medical metabolic disease like diabetes, rheumatoid arthritis. They were also excluded if they had reduced range of motion of the upper limb and cervical spine. Thirty female asymptomatic key board operators volunteered for the study (mean   Ã‚  Ã‚  Ã‚  age 31  ± 6.8 years; range: 24-54 years). Prior to the study all the participants read participation information sheet and signed consent form.   There after participants filled the evaluation form which was regarding inclusion criteria, years of experience, hours of work per day and arm dominance. Arm dominance was defined as the hand participants used for operating the mouse also referred to as mouse hand in the study. Participants were requested not to disclose information regarding their mouse hand during the study. The information pertaining arm dominance was blinded to both the researchers as it was known only after the application of ULTT1 test. Procedure Ethical approval was granted by the Committee on Ethics in Research at Sheffield Hallam University.   After the participants had filled the evaluation form and the participant was eligible for the study screening movements were performed on the cervical spine, thoracic spine and of both the upper limb to abolish these structures as potential resources of symptoms. Two researchers were involved in the study. Both were students of Msc Applying Physiotherapy at Sheffield Hallam University. The author was the primary researcher who performed ULTT1 on all the participants in both hands. The second researcher only assisted to record the response to ULTT1 on body chart. The method adopted to perform ULTT for median nerve was the test proposed by Elvey 1986, Kenneally et al 1988 and Butler 1991a. David Butler in 1991a conveyed ULTT1 to be median nerve dominant and was reliable in normal’s (Edgar et al 1994) and in patient population (Selvaratnam 1991). The ULTT 1 test was described to each participant by the prime researcher before the test is performed and were informed that their participation was utmost important while recording the response on the body chart. They were also informed to move any part of their body while describing their response to the assistant researcher. Each participant wore a vest for the research purpose. There after each participant lay supine on a high/low plinth with the test arm slightly off the plinth. For convenience researcher passively manoeuvres the test first on right hand followed by the left .The position was secured with seat belts around thorax and pelvis to avert lateral movement of the chest. The right arm was tested first for convenience and was placed in starting position with the glen humeral (G-H) joint in neutral, elbow flexed and forearm, wrist, fingers and thumb in neutral. The other arm will lay relaxed adjacent to the abdomen. The participants were advised to maintain the head in neutral position and were requested to look at a spot on ceiling which negated any cervical spine rotation. Thus with the neck in neutral position the ULTT 1 test was commenced. To start with the shoulder was positioned in to neutral position and the examiner placed the hand on the test shoulder to prevent elevation. This was followed by G-H joint abduction to a maximum of 110 ° in frontal plane. From this position wrist, fingers and thumb were passively extended the forearm was supinated. The G-H joint was then externally rotated to no more than 50 ° as the third distinct component to shoulder. Thus the last component to be added was elbow extension. The elbow was extended until full extension was achieved or participant reported any symptoms at any stage of the test. When the symptom were reported by the participant the second researcher was responsible to record the nature of perceived sensory response in form of words or phrases and the location of the perceived sensory response on a right side marked on body chart. There after structural differentiation (STD) i.e. ipsilateral neck flexion (INF) was performed by the actively. ULTT1 was considered mechanosensitive positive only if the participant perceived reduction in the perceived symptoms and if the primary researcher performing ULTT visually observed an increase in the   range of motion at elbow after the addition of desensitising manoeuvre i.e. the ipsilateral neck flexion (Quinter 1989, Butler 1990). The response of mechanosensitivity for ULTT was recorded as â€Å"Yes â€Å"or â€Å"No† and the response to structural deviation was recorded as increased (↑) or decreased (↓) with respect to symptoms only. A break of 10 minutes was given before the test was performed in the left hand. The same procedure was carried out and data was collected in similar manner on body chart.   Data Analysis Descriptive statistics were utilized to know if mechanosensitivity for ULTT1 exists in the participants. After data collection all the sensory responses were collated on a single body chart(figure 2) which as further analysed by dividing the upper limb into five distinct areas i.e. cubital, forearm, wrist, fingers and thumb. Frequencies of these locations were counted regardless of its nature and were tabulated. This made comparison between the two hands easier. The nature of perceived sensory response which was reported as words or phrases was divided in two categories stretch pain, pull pain. Frequency of the similar type of response was counted and compared for further analysis. Demographic characteristics like age, years of experience, hours of work and dominance were to analyse if association between ULTT1 response and these variables exists. To achieve the aim of the study, the data were analysed by answering the following questions. Analysis of the ULTT1 response in asymptomatic key board operators i.e. (mechanosensitive and the perceived sensory response from body chart). From the above analysis are there any evidence showing upper limb neurodynamic tests for median nerve is positive among asymptomatic key board operators? If â€Å"Yes† is there a difference in the response to ULTT1 when compared bilaterally? If there is a difference in response when compared bilaterally, is there an association between the hours of work, age and dominance with the ULTT1 response. The answers to these key questions further assisted in exploration of the research question: Is there a variability of response to upper limb neurodynamic test of median nerve in asymptomatic keyboard operators when compared bilaterally RESULTS Summary of mechanosensitive response compared between mouse and non mouse hand: Table 1 : Table of mechanosensitivity and sensory response in bilateral upper limbs. No Mousehand RIGHT ULTT 1 RIGHT STD    LEFT ULTT 1 LEFT STD Nature of perceived sensory response (R) Location of sensory response(R) Nature of perceived sensory response (L) Location of sensory response(L) 1 L Y ↓ Y ↓ Stretch pain 1,2,3 Stretch pain 1,2,3,4,5 2 R N ↓ N ↓ 3 R Y ↓ Y ↓ Pull pain 1,2,3,4,5 Pull pain 1,2 4 L Y ↓ Y ↓ Pull pain 1,2,3 Pull pain 1,2,3 5 R Y ↓ Y ↓ Stretch pain 1,2,3,4 Stretch pain 1,2,3   6 R Y ↓ Y ↓ Pull pain 1,2,3,4,5 Pull pain 1,2 7 R Y ↓ Y ↓ Pull pain 1,2,3,4,5 Pull pain 1,2,3,4 8 R Y ↓ Y ↓ Stretch pain 1,2,3,4 Stretch pain 1,2 9 R Y ↓ Y ↓ Stretch pain 1,2,3,4,5 Stretch pain 1,2,3,4 10 R Y ↓ Y ↓ Stretch pain 1,2,3,4 Stretch pain 1,2,3 11 R N ↓ N ↓ 12 R Y ↓ Y ↓ Pull pain 1,2,3,4,5 Pull pain 1,2,3,4,5 13 R Y ↓ Y ↓ Stretch pain 1,2,3,4,5 Stretch pain 1,2,3 14 R Y Y Pull pain 1,2,3,4 Pull pain 1,2,3 15 R Y ↓ Y ↓ Pull pain 1,2,3,4,5 Pull pain 1,2 16 R N ↓ N ↓ 17 R Y ↓ Y ↓ Stretch pain 1,2,3,4 Stretch pain 1,2 18 R Y ↓ Y ↓ Pull pain 1,2,3,4,5 Pull pain 1,2,3 19 R Y ↓ Y ↓ Stretch pain 1,2,3,4 Stretch pain 1,2,3 20 R Y Y Stretch pain 1,2,3,4 Stretch pain 1,2, 21 L Y ↓ Y ↓ Pull pain 1,2,3,4 Pull pain 1,2,3,4,5 22 R N ↓ N ↓ 23 R Y ↓ Y ↓ Pull pain 1,2,3 Pull pain 1,2,3, 24 R Y Y Stretch pain 1,2,3,4,5 Stretch pain 1,2 25 R Y ↓ Y ↓ Stretch pain 1,2,3,4,5 Stretch pain 1,2,3 26 L N ↓ N ↓ 27 R Y ↓ Y ↓ Pull pain 1,2,3,4 Pull pain 1,2 28 R Y ↓ Y ↓ Stretch pain 1,2,3,4,5 Stretch pain 1,2,3 29 R Y ↓ Y ↓ Pull pain 1,2,3,4,5 Pull pain 1,2,3 30 R Y ↓ Y ↓ Stretch pain 1,2,3,4 Stretch pain 1,2,3 ULTT1 Upper limb neural tissue tension test for median nere ; STD structural differentiation; INF: ipsilateral neck flexion      Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   Incidenc e of mechanosensitive response Fig1-Incidence of detected mechanosensitive response for ULTT 1 amongst asymptomatic keyboard operators From figure 1 it was evident that a high number of participants showed response for ULTT1. On adding ipsilateral neck flexion all of them perceived reduction in the symptoms Table 1.There was nobody who had complained of   unilateral symptoms.   Thus there was no difference in the mechanosensitive response to ULLT1 in the mouse and non mouse hand. Nature of the perceived sensory response and difference between the mouse and the non mouse hand After summarising the data from 30 body charts it was observed that 13 participants (43.33%) had complained of â€Å"stretch pain† and 12 participants (40%) had complained of â€Å"pull† pain (Table 1). After comparing the sensory response of mouse hand and non mouse hand in table 1, it was observed there was no difference in perceived sensory response in both the hands. Location of the perceived sensory response The location of perceived sensation in the right and left hand of all the participants were plotted on a single body chart. Figure 1 shows numerical involvement of location of symptoms for the ULTT1 amongst asymptomatic keyboard operators. Figure 1: Body chart divided into 5 areas where responses were perceived. After analysing the repsponse Graphs 2a and 2b :Comparing the symptoms in the mouse and the non mouse hand Location of response  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   Location of response From the graphs 2a and 2b it is clearly evident there was difference in the location of sensory response between the mouse and the non mouse hand. The median nerve was more sensititive in fingers and the wrist joints as compared to the non mouse hand. Discussion: Summary of the results The results from this study showed that asymptomatic keyboard operators showed a positive mechanosensitive response for ULTT1. There was no difference in the mechanosensitive and perceived sensory response when compared bilaterally. 83.33% participants had bilaterally positive mechanosensitive response and had shown increased area of symptoms in mouse hand. And on further reviewing individual characteristics of these participants there was no association found between with age, hours of work and years of experience. Byng 1997 compared the response of ULTT1 between patients, asymptomatic keyboard workers and asymptomatic non keyboard workers.   The results showed that key board operators had significant positive ULTT compared to non-keyboard user. Thus the current study and study performed by Byng et al 1997 proposes that a subclinical pathological condition exists in key board operators. There could be many reasons for such a scenario in this group of population. One of the reflection is the type of muscle exertion that is involved in the keyboard workers performing repetitive task for a prolonged hours causes static loading of neck and shoulder muscles (Subratty et al 2005). These static sustained contractions of the shoulders, neck and upper limbs may be required to fix the hands in a functional position necessary for the task (Pascarelli et al 2011). Along with this dynamic contraction of the forearm muscles are required for repetitive key actions which are then superimposed over this backg round of static muscular activity. The musculoskeletal system presents the nervous system with a mechanical interface (Butler 1989). A static muscle contraction such as those witnessed in key board users cause compression of a nerve there by reducing the mobility resulting in positive mechanosensitive response (Subratty et al 2005). The results of the study performed by Lohkamp et al 2011 were in contrast to the current study. He compared bilateral ULTT1 response in 90 normal individuals and the results showed that there were more neurogenic response and reduced ROM in the non dominant hand as compared to dominant hand. The difference in the result between the two studies could be attributed to the difference in the population involved. Lohkamp et al 2011 performed study on normal healthy individual who utilized their non-dominant hand less for their normal daily activities which could have led to reduced flexibility of muscles and compromised mobility of the nerve. In the present study since key board operation is a bilateral task such a difference was not observed. Structural differentiation is added to determine if the ULTT is positive or not (Butler 1991, Nee 2006). Depending on the type of structural differentiation applied, tension in the median nerve could be increased or decreased (Byl et al 2002).   In this study all the participants who had reported symptoms for ULTT1; 100% had reported decreased in the sensory response after adding structural differentiation (ipsilateral neck flexion). Similar results were reported by Selvaratnam et al 1994 and Scot et al 2008. This observation might be caused by decreased tensile force of the nerve causing increase in the circulation (Otaga and Niato, 1986). Similar results were seen in a study performed by Coopeiters et al 2002A which concluded that with structural differentiation there was a change in the ROM at the elbow joint and the frequency of response distal to it had reduced. Coopeiters et al 2002A also suggested performing contra lateral neck flexion as a structural differentiation to ULTT 1 as it causes more tension in the nerve tissue and is more specific in provoking the symptoms. But since this study was done in asymptomatic key board operators who are already exposed to high risk of developing overuse syndrome symptoms (Scot et al,2008),   contra lateral neck flexion was not the choice of STD in this study for ethical reasons. The present study found no difference in the perceived sensory response in the mouse and the non- mouse hand. Stretch and pull pain were the reported perceived symptoms. The literature reads that stretch and pull sensations are considered as normal response to ULTT1. An individual is considered as mechanosensitive positive if there is a decreased in the ROM while performing ULTT (Buttler1991). Even though the participants had shown response which was similar to normal’s they were still labelled as mechano sensitive for ULTT1 as the researcher had observed reduced ROM at elbow while performing ULTT but it was not measured. This further emphasise that asymptomatic key board users could have a hidden pathological state and are at high risk for developing repetitive stress injury syndromes. An understandable sample of frequency and nature of symptoms was recognized as there was not much of deviation. Amongst the participants who were mechanosensitive bilaterally 100% had perceived sensation at the cubital area (anterior aspect of elbow). The other common reported sites were forearm, wrist, fingers and thumb. The site of involvement was in accordance to the study put forth by Kenneally et al 1988 and Butler et al 1989. The 92% who had complained of more areas of response in mouse hand, had perceived symptoms in the cubital area   wrist fingers and thumb while the non dominant hand had received symptoms only in cubital area and forearm. The rationale for this could be the usage of the mouse itself.   Recent studies like Jepsen et al 2002 contributed to the literature by performing a cross sectional study on computer operators and concluded that pain, parasthesia and weakness were more prevalent in mouse arm as compared to non-mouse arm. The clinical reasoning behind this could be the mouse operating wrist is constantly positioned in a bent position and this causes reduced space in the carpal tunnel further reducing the mobility of median nerve and the other structures like tendon situated in it. Thus in the median exposed to more compressive forces in the mouse hand than the contra lateral limb and hence it becomes irritable and produces symptoms like tingling and numbness in the wrist, fingers and thumb. Also the difference in location of response had no association with age, hours of work and years of experience as these characteristics were no different than the other participants in the study similar result were observed by (Byng et al 1997) Theoretical Implication: From the current study it can be suggested that a subclinical pathological state exisits among female amongst the asymptomatic female key board operators supporting several hypothesis that the origin of repetitive stress injury are neurogenic in origin. This study also suggests that the usage of the mouse along with causes increased mechanosensitivity of median nerve in wrist fingers and thumb. Thus work place modification and ergonomic advise should also consider the mouse modification. Clinical Implication: Literature shows that dominant arm in normal’s could be used as a control group while assessing the ULTT1 response amongst symtomatics as there exists no variation in response to ULTT1 amongst normal healthy individuals. This study though performed on asymptomatic targeted an intermediate group and suggests that dominant arm is not a reliable diagnostic indicator as variability exists in the bilateral response with more response being in the dominant arm which is in contrast to the current literature. Strength of the study Limited research is available which compares bilateral response of ULTT1 thus the current study adds on to this limited literature. Also while ULTT1 was being conducted the researchers were blinded to the information of dominance to prevent assessor bias. The results obtained from the study could be generalizable as a large age group was included. Limitations Participants were labelled as mechanosesntitive positive if they had perceived a reduction in symptoms after adding ipsilateral neck flexion . No objecetive scale was used to find by how much the percentage the symptoms were reduced thus future research should incorporate scales like VAS scale to have more reliable results. The ULTT was carried out only ones on participants to label them as mechanosesntive positive. Thus this single reposne may not have recorded the real response. Ideally a mean of 3 response would be indiacted to prevent any errors. Scope for future research Future research should focus on more objective methods of accessing the variability of response ofULTT1 among symptomatic key board operators. If ROM is suggested as objective means to measure variability research should be carried out to know how much difference in ROM is required to label an individual mechanosensitive positive. 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The Origin of Wildfires and How They Are Caused

The Origin of Wildfires and How They Are Caused It is interesting to note that, of the four billion years of earths existence, conditions were not conducive for spontaneous wildfire until the last 400 million years. A naturally-occurring atmospheric fire did not have the chemical elements available until major several earth changes occurred. The earliest life forms emerged without needing oxygen (anaerobic organisms) to live about 3.5 billion years ago and lived in a carbon dioxide based atmosphere. Life forms that needed oxygen in small amounts (aerobic) came much later in the form of photosynthesizing blue-green algae and ultimately changed the earths atmospheric balance toward oxygen and away from carbon dioxide (co2). Photosynthesis increasingly dominated earths biology by initially creating and continuously increasing the earths percentage of oxygen in the air. Green plant growth then exploded and aerobic respiration became the biologic catalyst for terrestrial life. Around 600 million years ago and during the Paleozoic, conditions for natural combustion started developing with increasing speed. Wildfire Chemistry Fire needs fuel, oxygen, and heat to ignite and spread. Wherever forests grow, the fuel for forest fires is provided mainly by continued biomass production along with the resulting fuel load  of that vegetative growth. Oxygen is created in abundance by the photosynthesizing process of living green organisms so it is all around us in the air. All that is needed then is a source of heat to provide the exact chemistry combinations for a flame. When these natural combustibles (in the form of wood, leaves, brush) reach 572 º, gas in the steam given off reacts with oxygen to reach its flash point with a burst of flame. This flame then preheats surrounding fuels. In turn, other fuels heat up and the fire grows and spreads. If this spreading process is not controlled, you have a wildfire or uncontrolled forest fire. Depending on the geographic condition of the site and the vegetative fuels present, you might call these brush fires, forest fires, sage field fires, grass fires, woods fires, peat fires, bush fires, wildland fires, or veld fires. How Do Forest Fires Start? Naturally caused forest fires are usually started by dry lightning where little to no rain accompanies a stormy weather disturbance. Lightning randomly strikes the earth an average of 100 times each second or 3 billion times every year and has caused some of the most notable wildland fire disasters  in the western United States. Most lightning strikes occur in the North American southeast and southwest. Because they often occur in isolated locations with limited access, lightning fires burn more acres than human-caused starts. The average 10-year total of U.S. wildfire acres burned and caused by humans is 1.9 million acres where  2.1 million acres burned are lightning-caused. Still, human fire activity is the primary cause of wildfires, with nearly ten times the start rate of natural starts. Most of these human-caused fires are accidental, usually caused by carelessness or inattention by campers, hikers, or others traveling through wildland or by debris and garbage burners. Some are intentionally set by arsonists. Some human-caused fires are started to reduce heavy fuel buildup and used as a forest management tool. This is called a controlled or prescribed burn and used for wildfire fire fuel reduction, wildlife habitat enhancement, and debris clearing. They are not included in the above statistics and ultimately reduce wildfire numbers by reducing conditions that contribute to wildfire and forest fires. How Does Wildland Fire Spread? The three primary classes of wildland fires are surface, crown, and ground fires. Each classification  intensity depends on the quantity and types of fuels involved and their moisture content. These conditions have an effect on fire intensity and will determine how fast the fire will spread. Surface fires typically burn readily but at a low intensity and partially consume the entire fuel layer while presenting little danger to mature trees and root systems. Fuel buildup over many years will increase intensity and especially when associated with drought, can become a rapidly spreading ground fire. Regular controlled fire or prescribed burning effectively reduces the fuel buildup leading to a damaging ground fire.Crown fires generally result from intense rising ground fire heat and occur in the higher sections of draping trees. The resulting ladder effect causes hot surface or ground fires to climb the fuels into the canopy. This can increase the chance for embers to blow and branches to fall into unburned areas and increase the spread the fire.Ground fires are the most infrequent type of fire but make for very intense blazes that can potentially destroy all vegetation and organic manner, leaving only bare earth. These largest fires actually create their own winds and weat her, increasing the flow of oxygen and feeding the fire.