Tufts

P81208KKThe tufts of small branches that so often develop where limbs were pruned from the trunks of a coast live oaks are sometimes referred to as ‘tumbleweeds’. They are about the same size as an average tumbleweed. By the time the get any larger, most of the smaller stems have subordinated and died out, leaving only a few more defined dominant stems, which will continue the process until even fewer or a single new branch dominates. Such tumbleweeds, as well as stems that originated from such growth, are weakly attached to the main trunks. They often get pruned off for the same reason that the limbs that were there before got pruned off, or because they are expected to be weakly attached. If they remain long enough, they can of course develop into new limbs.

Tufts of the same sort of growth on sycamores or other deciduous trees are known more simply as . . . ‘tufts’ I bet you didn’t see that coming. They can get much bigger than tumbleweeds before they develop much distinction between the dominant and subordinate growth. Because tuft growth is innately vigorous, the leaves are bigger and coarser. Then, when the rest of the deciduous trees that produce them defoliate in autumn, the tufts retain their green foliage until it gets ruined by frost.

This big sycamore dropped its top over summer. https://tonytomeo.com/2018/07/14/nature-is-messy/ The tufts developed on the big trunks that became exposed to sunlight by the loss of the upper canopy above. The tree will naturally try to replace its top, but will also naturally be even more disfigured and structurally deficient than it already was. As the tufts develop into limbs, and the limbs get heavy with foliage, they will be very likely to break away and fall. As unpleasant as all that sounds, it is quite natural for such a mature sycamore who is so old that he just doesn’t care who gets offended anymore.

Arborists Are Very Specialized Horticulturists

81205thumbThe first storm of the year has a way of reminding us if our trees need attention. Whether then need to be worked on this year or not, we tend to notice how they blow in the wind, or if they are full of dead and deteriorating debris that falls into the garden or onto the roof. As deciduous trees defoliate, they are less likely to be damaged by wind, but their structural deficiencies become visible.
This is when some of us will contact arborists to inspect and perform necessary arboricultural procedures for trees that have grown to big for us to maintain. We do not want trees to be damaged by the wind. Nor do we want them dropping limbs or falling onto whatever is within their reach. Those that are biggest and most beyond our reach have the most potential to cause major damage.
Arborists are horticulturists who specialize in the horticulture of trees, which is known as arboriculture. They assess the healthy, stability and structural integrity of trees, then prescribe necessary corrective arboricultural procedures, and if necessary, prescribe the best time for such procedures. Most arborists work with a tree service that is equipped to perform the prescribed procedures.
Arborists who are certified by the International Society of Arboriculture, or ISA, have passed an examination of their arboricultural expertise, and maintain their credential by continued involvement with the educational seminars, classes and workshops of the ISA. More information about the ISA, local certified arborists and even arboriculture, can be found at the website http://www.isa-arbor.com.
As mentioned earlier, arboriculture is specialized horticulture of trees. It is not something that gardeners should be expected to perform; particularly mow, blow and go gardeners who are not even proficient with simple gardening. Many arborists can concur that unqualified gardeners sometimes kill trees, and cause much of the damage to trees that arborists must later correct. Besides, arboriculture is the sort of work that can be very dangerous to those who lack training, experience or the necessary equipment.

Bad Root Pruning

P81118-Root pruning is nothing new. It is done more commonly than we think about for many aggressive perennials like lily-of-the-Nile, that like to disperse their roots into areas where we want to grow more docile annual bedding plants or vegetables. We might do it halfway, or more, around a shrubby plant during spring or summer if we plant on digging and moving it the following autumn. For most small and low profile plants, root pruning is sort of tolerable. The plants that we do it to may not like it, but it is sometimes necessary, and better than not doing so.
Trees are not like most small and low profile plants. Most are very sensitive to root pruning when mature. They are not so proficient at replacing the portions of their root systems that they are deprived of. Large roots that get severed are very susceptible to decay, which slowly migrates inward to the rest of the root system. Obviously, depriving trees of roots compromises stability to some extent. Because roots are below grade, it is impossible to know the extent of the damage caused by root pruning while it is being performed. This is a classic example.
The exposed freshly cut surface to the left in the picture above is not the stump of a small tree that was just cut down. Although it is, in this picture, a horizontally oriented cut surface of what seems to have been something that was standing vertically, it was actually cut vertically through a horizontally oriented root. Yes, that is it in the yellow oval to the right. It was cut because it was displacing the adjacent asphalt pavement, as demonstrated by the picture below. Rather that trouble us with this concern, the resident of the adjacent home cut the root of this mature photinia tree to protect his driveway from more damage.P81118+

The problem was that the major root that was severed was all that was supporting the tree. (The cut surface of the severed root is in the middle of the picture below.) The roots to the left and right of it may seem to be substantial in the picture below, but were mostly decayed stubs left from earlier root pruning. I was able to wrestle the stump out to dispose of it, without cutting more roots. The lack of other substantial roots is probably why the primary root was so big and expanding actively enough to displace the pavement.P81118++

The funny thing about all this is that I would have done the same thing. I would have determined that, although the tree would be very distressed by the loss of such a major root, it should not have been too terribly destabilized, and should have been likely to eventually recover. Even if it eventually succumbed to the distress, the loss of this mature but small tree would have been a better option relative to continued damage to the paved driveway. I certainly would not have expected it to simply fall over as it so comically did. The picture below shows what had been vertical trunks of the photinia tree that were quite horizontal after it fell over. The fractured asphalt pavement is visible at the far right edge. The top of the tree reached the center line in the adjacent roadway. I am sorry that I did not get a more amusing picture of it blocking the lane. I was in too much of a rush to clear the roadway at the time. This was something that I really was not expecting to encounter at work.P81118+++

Big Trees Are Bad Houseplants

P81111By ‘big trees’, I don’t mean the various ficus trees that can grow up to the ceiling, and be quite happy inside. I am referring to the shade trees that live out in the yard, or forest trees that live beyond that. They are outside for a reason . . . or actually, several reasons. They are too big to bring inside. They probably would not like the climate inside. No one wants to rake fallen autumn leaves inside. Well, you get the point.
Unfortunately, on rare occasion, big trees that are outside end up partly inside by falling or dropping limbs onto the homes that they provide shade for. Just like trees seem to fall onto certain types of cars more than others ( tonytomeo.com/2018/11/04/trees-hate-cars ), trees seem to fall onto certain types of homes more than others. The difference between the homes that trees seem to dislike and the cars that they seem to dislike, is that there are actually reasons why some types of architecture is more susceptible to falling limbs or trees.
First of all, just as some trees seem to avoid falling on cars, some seem to avoid falling on houses.
Coastal redwoods in landscape situations are remarkably stable. In my entire career, I have inspected only three that have fallen. One had a massive pair of trunks that split apart and fell away from each other. Although they were on the fence line between two closely set urban homes, and there was almost no place for them to fall without destroying one home or another, they did the seemingly impossible. They literally fell onto the property line. One trunk fell out into the street. The other fell back into the backyards of the homes behind. The fence was pressed into the ground. The landscapes were seriously damaged. Gutters were stripped from both adjacent homes. Otherwise, there was NO structural damage to any of the homes. I am still amazed at how minimal the damage was!
The massive coast live oak two doors down from my former home in town was just as talented. It sprawled out over its associated home and the front yards of the two adjacent homes. It was so broad that I would not have believed that it could have fallen down without destroying one of the homes. Yet, it did exactly that . . . as I watched from my dining room. During a windy storm, it fell right toward me, and landed squarely in the front yard next door. It broke a few rafters on the edges of the eaves, and tore the gutters off, but that was the worst of the damage. It somehow found the best spot to fall where it would cause the least amount of damage.
Not all homes are so fortunate.
Victorian homes though, do not seem to be targeted by trees as much as others are. Most are closer to downtown, away from tall or very broad forest trees. Many are on somewhat narrow parcels that can not accommodate disproportionately large trees like the coast live oak in the picture above. Broadly sprawling trees tend to be too low to extend their limbs over the roofs of taller two story Victorian homes. Although taller than most other types of homes, two story Victorian homes do not occupy as much area as other homes, so are not such big targets.
Low profile homes of ranch architecture, or similar types of architecture, are more likely to be damaged by falling limbs or trees. Many happen to be located in suburban or rural areas, closer to bigger and broader forest trees. Their wider parcels can accommodate larger trees. Their roofs are low enough for trees to extend limbs over. Because they tend to be on a single level, they occupy more area, so are larger targets.

Trees Hate Cars

P71028That is a myth. They do not hate all cars. They just hate particular cars.
I did an internship with arborists in the summer of 1988, and have never been able to get away from arboriculture. Even as a nurseryman, I still sometimes work for arborists, and inspect trees that they are concerned with. I have seen many of their subject trees that have fallen onto parked cars, homes and whatever trees fall onto. I have noticed particular patterns.
Trees are more careful with Buick, Oldsmobile, Pontiac, Chrysler, Volkswagen, Mercedes Benz, and Datsun or Nissan. I have seen them put considerable effort into avoiding these cars when dropping limbs or falling over. When I was in school in San Luis Obispo, I drove my neighbor’s 1969 Oldsmobile Cutlass out from under his Chinese elm that fell over it. The tree held itself up on limbs that landed on the opposite side of the driveway so that the car came out from under it completely unharmed. When I lived in town in Los Gatos, a massive coast live oak two doors down fell harmlessly into the front yard next door. The roots pulled up in front of and behind a Volkswagen GTI that was parked at the curb, and barely tossed an ounce or two of mud onto the hood. A few big olive trees did the same at a large condominium complex in San Jose during a windy storm, leaving nothing more than a bunch of leaves and olives on top of a classic Mercedes Benz sedan and an old Datsun B210. These are certainly not the only examples. This seems to be a common theme for these particular cars.
I can not say the same for Mercury, Plymouth, Jeep, Cadillac, Mazda, Toyota, Lexus, Honda, Subaru, Infinity or Volvo. I have never seen trees damage or avoid damaging them.
Damage to Ford, Dodge, Audi, Isuzu and BMW did not see to be targeted. It was the sort of random damage that one would expect from a tree innocently falling onto parked cars.
Both of the only two cars that I know of that were squashed while being driven were Lincoln Navigators. That is not a good statistic at all. One was hit by a falling Canary Island pine in Fremont. The other was clobbered by a Coast live oak in Saratoga. No one was hurt; but the cars were killed.
I have seen only one Chevrolet damaged by a tree, but it was vicious! It was one of only three coastal redwood trees in a landscape situation that I had ever seen fall, although ‘fall’ does not adequately describe what this tree did. Without enough wind to damage adjacent and notoriously structurally deficient California pepper and Chinese elm trees, this redwood seemed to jump out of the ground to land on top of an Astro Van about twenty feet away! I do not think the tree was targeting it because it was a Chevrolet. The tree obviously hated this specific Astro Van VERY much.
Acura seems to be the second most hated sort of car among trees. They are less common than Honda, but I have never seen a Honda damaged by a tree that it did not run into first. Yet, I have seen at least three Acuras destroyed by a coast live oak, a blue gum eucalyptus and a Monterey pine. That is an inordinate number!
The car that trees seem to hate most is Porsche! They are uncommon cars, and are probably less common than any other car that I have ever seen damaged or destroyed by trees. Yet, I have probably seen more of them destroyed than Acuras, including one that was attacked as blatantly as the Astro Van was attacked by the small redwood. The ONLY blue spruce that I have ever seen fall landed squarely down the middle of a new Cayenne, back when they were the first SUV that Porsche made. The densely foliated canopy enveloped the car so thoroughly that only the middle of the tailgate was visible.
It would be interesting to know if insurance companies have determined if any particular types of cars are more likely to be damaged or destroyed by trees than any other. I would think that if the trends that I have noticed are accurate, that insurance companies would be aware of them as well. I am also curious to know if other arborists have noticed similar trends.P80106

Six on Saturday: Dia De Los Muertos

 

Dia de los Muertos, or Day of the Dead, was yesterday, Friday, November 2. However, the dead are still dead. They don’t need a special day to be so. In fact, they do it every day of the year. Dia de los Muertos is just one day of celebration to honor them.

Dia de los Muertos is not for plants though. Dead plants just get cut down and disposed of. Some get composted. Dead trees get recycled into firewood. These are six pictures of five species of dead plants that I needed to contend with in the week before last.

1. Rhododendron. I really do not know what killed this group of rhododendrons. It is not uncommon for one to die. With all the rhododendrons in the landscape here, a few dead ones get removed annually. However, it is rather disconcerting that a few died all in the same area at the same time. All their dead stems were rather sculptural. They were removed just after this picture was taken. Of the five specie in these six pictures, this is the only species that is not native.P81103

2. Madrone. Bits and pieces of madrone commonly succumb to blight, sort of like fireblight in apple and pear trees. Sometimes, entire trees are killed like this one. It is fire wood now.P81103+

3. Ponderosa pine. The forest does not burn as frequently as it used to before people were here to extinguish forest fires. The lack of restorative fires interferes with regional ecology. Not only is the forest becoming congested with unburned fuel, but pathogens are proliferating in the aging flora and consequently accelerating the deterioration of the forest, which increases the combustibility. It is a natural process designed to correct an unnatural lack of restorative fires, but does not go well for those of us who live here. Ponderosa pines can live for a few centuries. However, in our compromised ecosystem, many succumb to pathogens while still relatively young. This one will need to be removed next year. Once dead, they deteriorate and start to drop limbs within the year.P81103++

4. Coast live oak. This is one of the most adaptable of tree specie in California. It lives right down to the beach, and into interior valleys, and up the summit of the Santa Cruz Mountains. It does what it must to adapt to the various environments within its range. It often lives in groves of the same, where it is more likely to burn every few decades or so. In spacious valleys, it is often not so social, with individual trees living in relative isolation from their neighbors. Grass fires can burn harmlessly between such trees, allowing them to live for a few centuries. Wherever they are, they develop more trunks than they need. As they mature, subordinating trunks like this one, get shed naturally and harmlessly. It is not as bad as it looks. In the wild, it would rot and fall to the ground as the rest of the tree continues on as if nothing happened. In our landscape, it was cut and taken away.P81103+++

5. Coast live oak. This dead foliage is a bit more alarming because I do not know what caused it. It is probably superficial damage caused by a girdling beetle. I did not look for evidence. Sudden Oak Death Syndrome is a much more serious disease that is all too common here (and a very sensitive subject). Fortunately, this particular specimen is a small and unimportant tree that I would not mind cutting down if it were to succumb. I just do not like to be reminded of how rampant Sudden Oak Death Syndrome is here.P81103++++

6. Tan oak. This tree really did succumb to Sudden Oak Death Syndrome, Phytophthora ramorum, which is more commonly known here as SODS or SOD. A few adjacent tan oaks that succumbed last year are already very deteriorated and will soon be dropping limbs if not removed over winter. These particular trees are not very important to the surrounding forest. Their removal will actually improve the collective landscape, and give the surrounding redwoods more space to expand. The problem with SOD is that we never know which oaks it will kill next. It kills trees before we know they are infected. There is no remedy.P81103+++++

This is the link for Six on Saturday, for anyone else who would like to participate:

https://thepropagatorblog.wordpress.com/2017/09/18/six-on-saturday-a-participant-guide/

Straight And Narrow For Trees

30731thumbIn the wild, trees do just fine without any help from anyone else. They certainly are not stupid. Their roots disperse for adequate stability. Their trunks grow upward as limbs spread outward for adequate structural integrity. Trees only need help in landscape situations because they are expected to perform so unnaturally. From the very beginning, their trunks are bound and their roots are confined.

While they are growing in the nursery, trees are bound tightly to stakes to keep their trunks straight. Unfortunately, this binding inhibits natural development of trunk caliper. Since they can rely on stakes for support, trees do not waste resources on developing the strength of their own trunks. The various eucalypti are particularly sensitive, and can bend over to reach the ground when unbound.

Roots are confined to cans (pots) or boxes because that is how trees are grown in the nursery. Even in regions where trees are field grown, roots must be severed when trees get dug and moved. Many types of trees do not mind much, and are eager to disperse roots into a new landscape as soon as possible. However, oaks, pines and many others do not recover as efficiently from confinement.

Once in a new landscape, most trees need to be staked to recover from being staked and confined in the nursery. New sturdier stakes that extend below the confined root system into soil below should stabilize newly planted trees. This is particularly important for evergreen trees that will be blown more by wind than bare deciduous trees, and particularly because most trees get planted in autumn and winter.

These new stakes should be installed a few inches away from the tree trunks so that they can support the trunks loosely when the tightly binding nursery stakes gets removed. To prevent abrasion, new straps should be somewhat loose, and cross over between the trunks and stakes. A pair of opposing stakes, with straps supporting in opposing directions, is sturdier than a single stake. A few straps may be necessary.

The new crepe myrtle trees in the picture above remain  bound to the stakes that they were grown with in the nursery. Sturdier stakes that can support the trunk in a less constrictive manner have yet to be installed.

KinderGarden

P81028

By modern standards, the public schools that I attended in the early 1970s would be considered to be bleak and primitive. The building were utilitarian and simple, from about twenty years earlier. The landscaping was comparably simple, with a big lawn and proportionately big shade trees. A screen of alternating Monterey pine and Monterey cypress was hedged on the southern half of the eastern boundary of the schoolyard. The only deviants to the simplicity were a few significantly older trees on the northern half of the eastern boundary of the school yard. There were two coastal redwoods, a Canary Island date palm, a cedar, and a spruce of some sort. They were all quite mature, and were likely remnants from an old farmhouse that was there before. Perhaps they wanted us to be aware that everything changes.
On the way to kindergarten, back when children were allowed to walk to school, I weaseled my way underneath the first Monterey pine and Monterey cypress on the southern end of the fence line, and fell asleep. I do not remember how long I stayed there, but it was long enough to get in serious trouble with my very worried kindergarten teacher. After that, I could only visit those two trees in passing, and perhaps stop only briefly to smell the foliage or shake some of the rain away.
Nearly four decades later, but only a few years ago, I was assigned the grim task of composing the arborist report that would justify the issuance of a permit to remove that same Monterey pine, which was the last that remained of the hedged trees that I remember. I did not know that when I went to the site. I was just told that it was a ‘pine’.
Visiting the old school was not a pleasant experience. The entire site was surrounded with a prison like fence and saran screens to obscure the view inside and out. There were no open gates. I needed to be escorted to the tree by a professional chaperone. Much of the schoolyard had been very synthetically landscaped with microtrees and pretty flowering shrubbery that was intended to impress parents rather than appeal to children. It is bad enough that there are no orchards or open spaces remaining in the region, but it is worse that children are deprived of the open lawns and trees and natural spaces that my generation had taken for granted on the grounds of our school. Are children even allowed to climb trees anymore? Do they know what dirt is? Can they observe a chrysalis split open to reveal a new butterfly before the gardeners shear the shrubbery and take the learning experience away? It was saddening.
Once I realized that the tree that I was expected to condemn was my old friend, I asked the chaperone, who seemed to know a bit about facilities at the site, why anyone would want the now mature tree to be removed. I knew that it had been mutilated while young, but was impressed with how it somehow recovered and developed a well structured trunk. I thought that perhaps someone noticed something that I was missing in my inspection. People who are not arborists are sometimes alarmed by something that is perfectly normal for a tree, such as furrowed bark, or slight seasonal foliar discoloration.
The chaperone explained that the tree needed to be removed simply because it did not conform to the style of the rest of the landscape. I waited for the rest of the answer, but that was it. The tree did not conform.
Nothing gave me more pleasure than to explain that after my evaluation of the health, stability and structural integrity of the subject, I could find no justification for removal.
I was dismissed.
Yes, it was worth it.
However, I knew that for the right price, another arborist would be pleased to condemn the tree. The picture of what remains suggests that the arborist who did so was not even professional enough to get his crew to finish the job. How does this dead stump conform to the rest of the landscape?
Those old trees, the redwoods, palm, cedar and spruce, were right. Everything changes.
The Monterey pine that would not conform is gone now, but it was right too.

Horridculture – Arborists Are . . . Unique.

80221thumbThere are many different types of horticulturists. We are all unique, both individually as well as collectively within our respective professional group classifications. For some of us, individuality interferes with conformity to the collective generalizations that are so commonly associated with our collective groups. For some of us, the stereotypes are a perfect fit.
‘Primarily’, I am a nurseryman. We are the intellectual ones. Well, at least we get most of the credit for being the intellectual ones. Most of us really are quite intellectual. Most of us are rather humble about it.
My excuse for nonconformity to the latter is that I am ‘secondarily’ an arborist. Arboriculture is something that I have never been able to get away from. I did an internship with the most excellent arborists in the entire universe in the summer of 1988. After all these years of mostly growing horticultural commodities, I still sometimes conduct inspections and compile reports for trees that other arborists and their clients are concerned about.
You see, arborists are the passionate ones. One might say that we are enthusiastic, fanatical and zealous. Nurseryman might say that we lack restraint and cultural refinement. It is not such a simple task to distinguish between exuberant dedication and primitive efficiency. Regardless, most arborists do not like to write reports. It is easier to get a nurseryman to do it.
In fact, arborists do not like to write much of anything. There are several elaborate blogs that are written by nurserymen; but blogs written by arborists are rare, with brief and infrequently posted articles.
The irony of this is that it is more important for arborists to express professionalism with clients than it is for nurserymen. Arborists are out in the real world, working directly with clients. Nurserymen work on the farm, isolated from those who purchase the horticultural commodities that are grown there.
Arborists are horticulturists who specialize in the horticulture of trees. The best are just as educated and experienced as nurserymen are. In fact, much of my education was derived from arborists. Yet, arborists are so often regarded as mere gardeners who go up trees.
That is where I get offended. Yes, I am aware that there are hackers out there. I am also aware of what clearance pruning of utility cables entails. I also know how serious my arborist colleagues are about their profession. They are not to be compared to gardeners.
There are many gardeners who are just as educated, experienced and proficient with horticulture as arborists and nurserymen. However, the majority of gardeners are not. I will not elaborate on this presently. It will be the subject of other rants. I have written articles about my professional experience with gardeners already, and none of them go well. (I lack experience with good gardeners simply because they have no need for my expertise.)
The picture above is an example of a sycamore that is pollarded in the traditional English style. The work is exemplary, and is repeated annually every winter. It is no simple task. I certainly would not want to do it. I can not think of any other nurseryman who would know how to do it properly. It is the work of a very skilled and very experienced arborist.

Six on Saturday: Clearance

 

Clearance can get one into some interesting situations. Yes, with the necessary clearance, one can get into penitentiaries, protected military facilities, sensitive areas of the White House, or even Area 51.

The sort of clearance that I was concerned with this past week and the week prior was not so interesting. Now that roofs and gutters of the buildings at work are in the process of being cleaned before wintry weather, trees must also be pruned for clearance. As they grew through summer, some got detrimentally close to the roofs and gutters that are getting cleaned, as well as chimneys, windows, outdoor lighting and walkways. Such clearance is a concern throughout the year, but becomes more of a priority as we get ready for winter. No one wants to go back onto the roofs any more than necessary.

1. Before. The redwoods must be pruned for adequate clearance from the roof, chimney, lamppost, and even the umbrella on the patio that can not be opened without pushing a bit of foliage aside.P81013

2. After.P81013+

3. Soot on the tip of one of the redwood limbs demonstrates why clearance from chimneys is so important. Foliage that gets too close to chimneys can ignite and fall back onto the roof below, where it has the potential to ignite any foliar debris that might have accumulated behind the chimney since last year.P81013++

4. The belfry of the chapel next door really bothered me. Clearance was barely adequate. Although I am not worried about the shingles or painted surfaced getting damaged as wind starts to blow during winter, I think that the chapel would look better with more clearance from the encroaching redwood limbs. The problem was that I could not reach the limbs. Because this clearance was not a priority, the pruning here was postponed. A colleague who is not as plump as I am suggested that I get onto the roof through that gap between the top of the louvered sides of the belfry, and the underside of the roof above. Now, even if I could somehow get through that little gap, where would I go on the outside?! Let Quasimodo do it!P81013+++

5. The chapel was built among the redwoods, very literally. Expanding trunks are beginning to displace the foundation and utilities. I can not prune for the sort of clearance that is needed here. Because the chapel is such an important building, and the redwoods are such important trees, it would be feasible to move the chapel over onto a new foundation. The problem with that idea is that the redwood trunks are pressing up against the building on three sides! There is no place to move the building without cutting something out!P81013++++

6. Phytophthora ramorum, which is commonly known as Sudden Oak Death Syndrome, or SODS, continues to kill tanoaks, (Notho)lithocarpus densiflorus, and coast live oaks, Quercus agrifolia. These trees do not need to be pruned for clearance, but must be removed before they start to deteriorate and drop limbs onto adjacent buildings or whatever happens to be below.P81013+++++

This is the link for Six on Saturday, for anyone else who would like to participate:

https://thepropagatorblog.wordpress.com/2017/09/18/six-on-saturday-a-participant-guide/